2015 Conference on Low Dimensional Science
International Workshop on Frontiers of Nanoscience and Condensed Matter Physics
May 18-22, 2015, Taichung, Taiwan
Department of Physics and Institute of Nanoscience, National Chung Hsing University, Taiwan
School of Physics and Engineering, Zhengzhou University, China
Department of Physics and Institute of nanoscience, NCHU, Taiwan School of Physics and Engineering, Zhengzhou University, Henan
International Laboratory for Quantum Functional Materials of Henan, China
Department of Physics, NCUE, Taiwan Department of Physics, THU, Taiwan College of Science, NCHU
Research Center for Sustainable Energy and Nanotechnology, NCHU High-performance Computing Division, NCHC, Taiwan
Professor Maw-Rong Lee, 李茂榮 (Dean of the college of science, NCHU) Prof. Xi-He Tian, 田西和 ( School of the Physics and Engineering, ZZU)
Professor Mon-Shu Ho, 何孟書 (National Chung Hsing University, Taiwan) Professor Yu Jia, 賈 瑜 (Zhengzhou University, China)
Academic Advisory Committee：
Prof. Yuen-Wuu Suen, 孫允武 (Chair of the Department of Physics, NCHU) Prof. Ming-Way Lee, 李明威 (Chair of the Institute of Nanoscience, NCHU) Prof. J. C. Wu, 吳仲卿 (Department of Physics, NCUE) Prof. Forest S.-S. Chien, 簡世森 (Department of Physics, THU) Prof. Watson Kuo, 郭華丞 (Department of Physics, NCHU) Prof. Maonan Zhang, 張茂男 (Department of Physics, NCHU) Dr. Wansheng Su, 蘇萬生 (High-performance Computing Division, NCHC)
Prof. Chiu-Hsien Wu, 吳秋賢; Prof. Lan Kenneth Ming-Der, 藍明德;
Prof. Chia-chien Huang, 黃家健; Prof. Hui-Yu Chen, 陳惠玉, Prof. Yen-Fu Lin 林彥甫; Prof. Guang-Yin Chen, 陳光胤
Contacts：陳佳君 04-22840427 ext 621; email: firstname.lastname@example.org
Low Dimension Science
Since 2010, Low Dimensional Science Workshop has been held three times a year:
Spring, summer and autumn. The workshop was pioneered by researchers situated in central Taiwan to meet and greet researchers with the same interest; Low Dimensional Science – which is how the workshop got its name. Every workshop consists of ~150 attendees who have travelled from different universities all over Taiwan; all with different backgrounds and studies of interests: Students, professors and researchers from Academia Sinica, National Taiwan University, National Cheng Kung University, Chiayi University are but some of the participants that can be seen at the workshop.
This workshop is not restricted to Taiwanese researchers only: Researchers from China are also invited as guest speakers to promote and present their research. We hope to use the opportunity of hosting The 2nd International Workshop on Frontiers of Nanoscience and Condensed Matter Physics, together with Zhengzhou University, to form a tighter relationship with China and not just have the geographical advantage.
With the common language being physics, we hope to bring researchers from China and Taiwan closer to one another through understanding each other’s passion and fields of study. This conference offers an opportunity to mingle and hopefully long lasting long distant relationships will be formed. Through these relationships, correspondence with regards to study topics can be allowed for.
During LDS, many researchers will be presenting on the work that they are either knee deep in, or have just gotten their hands on. Through attendance of the LDS, hopefully you can give your ideas and have opportunities to ask and exchange thoughts and in addition, keep pace with the rapid change that is happening within your field of study. Thus through alliance in hosting The 2nd International Workshop on Frontiers of Nanoscience and Condensed Matter Physics, we invite researchers from both China and Taiwan who excel in their field of study to accompany us in discovering the exciting world of LDS. This includes researchers from Zhengzhou University, Fudan University, Shanghai Academy of Science and Technology , Henan Normal University , etc. With the topic mainly focusing on Nano materials science and condensed matter physics and low-dimensional science, it will allow for in depth exchange in ideas, opinions and thoughts and have researchers leaving with new and budding friendships and ideas.
Introduction to National Chung Hsing University
National Chung Hsing University (NCHU), located in Taichung city, is one of the most historic university in Taiwan. Adjacent to Taichung Precision Science Park, NCHU is the most important academic, research and internet center in central Taiwan.
It was founded in 1919 in the Roosevelt Road Campus of National Taiwan University, and was then moved to its present location in 1943. With overall 18,000 students and nearly one thousands of faculties, it is the third largest comprehensive national university in Taiwan, and is one of the 100 top universities in Asia. NCHU is famous of its excellent Agricultural Science, Veterinary, Life Science, Environmental Conservation, Biotechnology and Fire Prevention Information.
Focusing on the developing into a comprehensive research university, NCHU devoted to researches on cutting-edge science and technologies. Meanwhile it has carried on transformation and integration within the campus. The faculties of the College of Science and College of Engineering collaborated in the research on nano technology and science. With clear academic planning, they has constructed the nano technology talents pool, organized many seminar and forum, and set up Nano Technology and Science Center to foster the educational, research and industrial development of nano technology and science.
NCHU has become one of the top universities in Taiwan since the school was granted under the "Development Plan for World Class Universities and Research Centers of Excellence program" funded by the Ministry of Education in 2006. In September, 2010, the Extension Division for In-service and Continuing Education was transformed into the School of Innovation and Industry Liaison. In August, 2011, the College of Social Science & Management was renamed as the College of Management, and the College of Law and Politics was established at the same time.
The main campus contains the College of Liberal Arts, the College of Agriculture and Natural Resources, the College of Science, the College of Engineering, the College of Life Sciences, the College of Veterinary Medicine, the College of Management, the College of Law and Politics, and the School of Innovation and Industry Liaison. It is located in the south of Taichung City and has an area of approximately 53 hectares.
Introduction to Zhengzhou University
Zhengzhou University (ZZU), located in Henan province, was founded on 2000 through the annexation of the former Zhengzhou University, Zhengzhou University of Technology and Henan Medical University. It has developed into a comprehensive university with 13 disciplines of Philosophy, Science, Engineering, Medicine, Literature, History, Law, Economics, Management, Art and so on.
Zhengzhou University is one of the national “211 project” key university. Under the sponsor of the Ministry of Education, it is the sole university in Henan Province supported by “The Midwest Universities Comprehensive Strength Promotion Project”
and “Excellence Engineers’ Education Program”. The Chemistry, Material Science, Clinical Medicine and Engineering programs in Zhengzhou University are top 1% all over the world in the ESI rank. Zhengzhou University ranked 36 in the “China University Rankings” and it is one of the top 500 global institutes. It has been honored as “Flag of High Education” and was supported by the State Council to create “County’s Top University”. The campus of Zhengzhou University is recognized as “One of The Most Beautiful Campus in China” and it is an excellent representative of the universities in the north of China.
By 2013, Zhengzhou University has been equipped with educational facilities with total value of 505 million RMB. The University Library contains a collection of books of more than 7.911 million and has its own publish house, which issue 13 academic journals. With overall areas of 6493mu, Zhengzhou University has at present over 49,000 full-time undergraduates, 15,000 full-time postgraduates and 1,100 international students. Meanwhile, there are over 6,000 full-time staff members, among whom 35 are members of CAS or CAE and 37 are awarded by the Ministry of Education as "Changjiang Scholar". Backed up with a sound talent nurturing system, Zhengzhou University has 46 faculties, offering 104 undergraduate programs and 21 doctorate programs of the first-level discipline. In addition, the university has 2 national keystone disciplines and 6 national scientific research institutions including the “National Engineering Research Center”.
Introduction of National Changhua University of Education
Formerly named Taiwan Provincial College of Education, this university was established in 1971, then granted university status and renamed National Changhua University of Education in 1989. As central Taiwan’s only comprehensive university specializing in teacher education, NCUE also embraces the nature, meets the challenges, visualizes the future, searches for excellence, and strives hard to obtain grants to create a research-friendly environment. It has founded prizes to encourage innovative research while making effective use of the integrated resources to create unique characters.
NCUE’s two campuses, Jin-De and Bao-Shan, are home to seven colleges. These comprise 21 departments, 46 graduate programs, and 15 doctoral programs to offer a well-planned and enriching study environment.
NCUE aspires to become a first-rate university that equally emphasizes teaching, research, and service in order to foster students' general and professional knowledge, improve our faculty's professionalism, achieve national and international recognition, enhance our competitive edge, and achieve sustainable development.
Introduction to Tunghai University
Tunghai University was established in 1955 and it is located on the level plateau of Taichung’s Tatu Mountain. Tunghai University, a liberal institution is full of scholarly elites and abundant resources and is well-known for its beautiful campus.
Tunghai has 8 colleges, 34 departments and 35 Master’s programs (1 independent Master’s program and 13 In-Service Master’s programs) and 14 PhD programs.
Tunghai currently has 8 colleges: College of Arts, College of Science, College of Engineering, College of Management, College of Social Sciences, College of
Agriculture, College of Fine Arts and Creative Design, and College of Law. Tunghai has a student body of approximately 17,000 students and close to 500 teachers (88%
of assistant professors and above). The total area of Tunghai’s campus reaches 1,333,096 square feet. With its spacious campus, Tunghai has the ideal teaching and learning environment for each and every Tunghai faculty and student.
Not only has Tunghai University received high rankings in reviews and topped recruiter rankings, but Tunghai also has received outstanding results from Ministry Of Education and has received 4.84 billion of subsidies from MOE’s Teaching
Excellence Project for 6 consecutive years. With the above mentioned outstanding review results and MOE subsidies received, they have shown that Tunghai’s constant pursuit of excellence in both teaching and overall university development have been publicly recognized.
Tunghai University is renowned for its picturesque campus and landmarks, which provide an ideal environment to conduct teaching and research. Luce Chapel is one of Tunghai’s most famous and visited landmarks. The Luce Chapel, the world-known architectural masterpiece, was designed by architecture masters I. M. Pei and C. K.
2015/5/18 DAY 1
08:30~ 09:45 校園巡禮
09:50~ 10:30 中興大學與鄭州大學姊妹校簽約儀式 (國農大樓 1F)
1. 中興大學國際長: Prof. Sy-Sang Liaw, 廖思善 教授 2. 中興大學理學院院長: Maw-Rong Lee,李茂榮 院長 3. 鄭州大學物理工程學院: Prof. Xi-He Tian, 田西和 教授 4. 鄭州大學國際事務處: Prof. Bin-Yu Zhao, 趙賓予教授
10:30~ 11:00 Low Dimensional Science Opening Ceremony(國農大樓 1F) Chair:
Prof. Mon-Shu Ho, 何孟書 教授
Prof. Jia Yu, 賈 瑜 教授
1.中興大學理學院院長: Prof. Maw-Rong Lee, 李茂榮 院長 2.中興大學工學院院長: Prof. Fu-Sheng Hsueh, 薛富盛 院長 3.NARLabs 國網中心: Prof. Chun-Hui Tsai, 蔡俊輝 副主任 4.鄭州大學物理工程學院: Prof. Xin-Jian Li, 李新建 副院長
5.鄭州大學科學與技術研究院: Prof. Xueqing Wang, 王雪青副院長 6.彰化師範大學理學院院長: Prof. Lien-Hui Hung, 洪連輝 院長 7.東海大學物理系: Prof. Shih-Sen Chien, 簡世森 教授
8.中興大學物理系主任: Prof. Yuen-Wuu Suen, 孫允武 教授 11:00~ 12:00 Plenary Session (國農大樓 1F)
Prof. Jong-Ching Wu, 吳仲卿 教授 Prof. Xin-Jian Li,
Prof. Po-Wen Chiu, 邱博文 教授 (NTHU) Towards 2D electronics: from growth to physics and
Prof. Jung-Chun Huang, 黃榮俊 教授(NCKU) Tailoring of low dimensional materials of bismuth on
monolayer epitaxial graphene
14:00~15:00 Plenary Session (國農大樓 1F) Chair:
Prof. Yuen-Wuu Suen 孫允武 教授 Prof. Liang-Yao Chen
Prof. Jia Yu, 賈瑜 教授 (ZZU)
The anomalous electronic and magnetic properties in black phosphorene
Prof. Song-You Wang, 王松有 教授 (FDU) Broadband optical absorption tunable by Mie
resonance in silicon nanocone arrays Chair:
Prof. Watson Kuo 郭華丞 教授 Prof. Zong-Xian Yang,
Dr. Nan-yu Chen, 陳南佑 博士 (NCHC) simPlatform－開放式高速計算平台 15:20~15:40
Quantum Transport of Charge Carriers in Graphene and its
Application to Nanoelectronics
15:40~ 16:00 Coffee Break
16:00~ 17:40 Invited Talks (國農大樓 1F) Chair:
Prof. Mon-Shu Ho, 何孟書 教授 Prof. Rong-Jun Zhang,
Prof. Xin-Jian Li, 李新建 教授 (ZZU) Adjustable white light emission based on CdS / Si
hetero-structures on a nanometer scale for multi- interface for an array of color temperature 16:20~16:40
Prof. Chia-Ching Chang, 張家靖 教授 (NCTU) DNA guided nickel ionS chain memristive system
Prof. Kuen-Lin Chen, 陳坤麟 教授 Prof. Ying-Jiu Zhang,
Prof. Liang-Yao Chen, 陳良堯 教授 (FDU) Research in light wave propagation mechanism of
precious metal-based interface 17:00~17:20
Prof. Jong-Ching Wu, 吳仲卿 教授(NCUE) Electrical transport in nanostructured magnetic tunnel junctions with low resistance-area product
Prof. Zong-Xian Yang, 楊宗獻 教授 (HenanNU) DFT Study on the Mechanism of Sulfur Poisoning and
Coke formation on the Anode of SOFC
17:40~ 18:30 Dinner
18:30~ 20:00 Chair:
Prof. Yuen-Wuu Suen 孫允武 教授
Converse on recent achievements in Physics
2015/5/19 DAY 2
9:00~10:20 Invited Talks (理學大樓 S104) Chair:
Prof. Chia-Chien Huang, 黃家健 教授 Prof. Song-You Wang,
Prof. Watson Kuo, 郭華丞 教授 (NCHU) Quantum optics in 3-level superconducting artificial
Prof. Rong-Jun Zhang, 張榮君 教授 (FDU) The optical properties of nanoscale thin films studied
by spectroscopic ellipsometry Chair:
Dr. Wen-Jay Lee, 李玟頡 博士 Prof. Shun-Fang Li,
Prof. Ying-Jiu Zhang, 張迎九 教授 (ZZU) Excellent separation and filtration membrance:
Graphene oxide (GO) film 10:00~10:20
Prof. Tsong-Shin Lim, 林宗欣 教授 (THU) Estimate the number of emitters in a fluorescent
10:20~10:35 Coffee Break
10:35~12:05 Invited talk from the Science and Technology Industry (理學大樓 S104) Chair:
Prof. Mao-Nan Chang, 張茂男 教授 Prof. Yu-Zong Gu
Recent advances and new applications in Bio AFM, Raman AFM and IR AFM
顧玉宗 教授 Prof. Gu-Jin Hu,
EPISTAR Corporation 人才招募說明
12:05~14:00 Lunch Converse on recent achievements in Physics (理學大樓 601)
Prof. Yuen-Wuu Suen 孫允武 教授 Prof. Xi-He Tian,
田西和 教授 Prof. Feng-Fei Rao
14:00~15:50 Invited Talks (理學大樓 S104) Chair:
Prof. Guang-Yin Chen, 陳光胤 教授 Prof. Er-Jun Liang
Prof. Feng-Chuan Chuang, 莊豐權 教授 (NSYSU) Prediction of two dimensional topological insulators in
honeycomb structure 14:20~14:40
Prof. Gu-Jin Hu, 胡古今 教授 (SARI CAS) Formation mechanism of quasiperiodic ferroelectric
Prof. Chiu-Hsien Wu, 吳秋賢 教授 Prof. Chong Li,
李 沖 教授
Prof. Ming-Ju Chao, 晁明舉 教授 (ZZU) Electrical properties of Al–ZrMgMo3O12 with
controllable thermal expansion 15:00~15:20
Prof. Chong Li, 李 冲 教授 (ZZU)
Anomalous Wilson transition in diagonal phosphorene nanoribbons driven by strain
15:20~15:50 Student Oral Presentation A (理學大樓 S104) Chair:
Guan-Hao Chen (THU)
Fluorescence Saturation of Fluorescent Nanodiamonds 15:35~15:50
Pin-Han Huang (THU) Thermal transition of (N-V)－ centers in fluorescent
2015/5/20 DAY 3
9:00~10:20 Invited Talks (理學大樓 S104) Chair:
Prof. Yen-Fu Lin, 林彥甫 教授 Prof. Ming-Ju Chao,
Dr. Rui Zhang, 張 瑞 博士 (WHU)
Graphene synthesis by ion implantation technique 9:20~9:40
Prof. Qiang Sun, 孫 強 教授 (ZZU)
Theoretical study of hydration in A2Mo3O12 family materials
Prof. Hui-Yu Chen, 陳惠玉 教授
Prof. Shun-Fang Li, 李順方 教授 (ZZU)
Catalysis in the Single-Atom Regime Governed by the Interplay between a Generalized d-Band Model and
the Spin-Selection Rule
15:50~16:10 Coffee Break
16:10~17:40 Student Oral Presentation B (理學大樓 S104) Chair:
Dr. Rui Zhang, 張 瑞 博士
Chen-Hui Li (ZZU)
Thickness dependent of phase shift between surface energy and work function in Pb ultrathin films 16:25~16:40
Xiao-Yan Ren (ZZU)
Quantum Tunneling at Si(100) Surface when exposed to Electric Fields or under Charge Injection 16:40~16:55
Xing-Ju Zhao (ZZU) Friction quantum size effects in 1D atomic chain 16:55~17:10
Rui-Feng Chang (NCHU) Investigate the graphene flakes expanded by graphite
intercalation compounds 17:10~17:25
Chung-Yui Lin (NCHU) The pn junction images under open-circuit and
19:00~20:30 The future in Physics for China and Taiwan (理學大樓 3A12)
Prof. Qiang Sun, 孫 強 教授
Prof. Yen-Fu Lin, 林彥甫 教授 (NCHU) Nanocontact disorder in nanoelectronics
10:20~10:40 Coffee Break
10:40~12:00 Student Oral Presentation C (理學大樓 S104) Chair:
Siti Utari Rahayu 博士生
Ph.D. student Chen-Hui Li, 李晨輝 博士生
Das Bipul (NCUE) Low frequency noise characterization of
CoFeB/MgO/CoFeB MTJ based 10:55~11:10
Tunnel magnetoresistance in high aspect ratio ellipse devices
Domain Wall Motion in Notch-Patterned Permalloy Nanowire Devices
李國維 (NCUE) Spin valve magnetic field sensor 11:40~11:55
Investigation of flux guide for integrating three-axis magnetic field sensors by electroplating permalloy
13:30~14:50 Student Oral Presentation D (理學大樓 S104)
Visitation of Technology Plantations by invitation
Bipul Das 博士生
Ph.D. student Xiao-Yan Ren, 任曉燕 博士生
Yen-Hung Ho (NTHU) Spin and Valley Polarizations in Transition Metal
Dichalcogenide Monolayers 13:45~14:00
Chi-Yang Lin (NCUE) Pinning domain wall by using NiFe/IrMn exchange
Sheng-Feng Lu (FCU) Study of the Electro-Optical Behavior on BPIII 14:15~14:30 Yuan-Hsiang Hsieh (NCHU)
Two Superconducting Qubits Coupled to Microwave
(D4) Resonator 14:30~14:45
Yong-Hong Chen (NCHU)
Using image recognition technology to identify the similarity simulation of surface atoms and
experimental atomic structure
14:45~15:05 Coffee Break
15:05~16:00 Student Oral Presentation E (理學大樓 S104) Chair:
Ph.D. student Xing-Ju Zhao,
Pb-Sb-S 量子點固態半導體敏化太陽能電池特性 15:20~15:35
Nipapon Suriyawong (NCHU) CuBiS2 Quantum Dot-Sensitized Solar Cells by
Chemical Bath Deposition Method 15:35~15:50
Yen-Chen Zeng (NCHU) Pb-Sn-S Semiconductor-Sensitized Solar Cells 15:50~16:05
ZnO-doped TiO2 Photo-anodes for Dye-Sensitized Solar Cells
16:05~16:20 Coffee Break
16:20~17:00 LDS Closing ceremony (理學大樓 S104)
19:00~20:30 Discussion of LDS in recent years and expectations in the future (理學大樓 3A12)
2015/5/21 DAY 4
9:00~12:00 Future expectations for the field of Physics Chair:
Prof. Yuen-Wuu Suen, 孫允武 教授
15:00~16:00 Head towards 惠蓀
16:30~18:00 Future expectations for the field of Physics Chair:
Dr. Wan-Sheng, 蘇萬生 教授
19:30~21:00 Future expectations for the field of Physics Chair:
Prof. Chia-Chien Huang, 黃家健 教授 Prof. Yen-Fu Lin,
林彥甫 教授 Dr. Wan-Sheng,
Women in Physics Chair:
陳惠玉 教授 Prof. Guang-Yin Chen,
陳光胤 教授 Prof. Hui-Yu Chen,
2015/5/22 DAY 5
8:30~11:00 Breakfast & then heading towards to NCTU 11:00~12:00
Prof. Kien-Wen Sun, 孫建文 教授
Center for Nano Science and Technology at NCTU
14:00~17:00 Discussion of future co-operation with perspective parties as well as future expectations
Closing ceremony Prof. Yuen-Wuu Suen,
Prof. Bin-Yu Zhao, 趙賓予 教授
Prof. Xueqing Wang, 王雪青 教授
Prof. Cen-Shawn Wu, 吳憲昌 教授
Towards 2D electronics: from growth to physics and applications (P1)
P. W. Chiu
Department of Electric Engineering & Institute of Electronic Energineering, National Tsing Hua University, Tainan, Taiwan 300, Taiwan
Graphnene continues to attract great attention in both academia and industrial. The most exotic properties of graphene includes: (1) the lowest electrical resistivity; (2) the highest planar thermal conductivity; (3) the highest signal transmission; (4) high light transparency; (5) high chemical inertness; (6) high flexibility; (7) high
mechanical strength; (8) low mechanical friction. In this talk, I will start with the fundamental growth of graphene using different approaches that provide clues to our better understanding of graphene synthesis and structural properties. In the second part, physics of graphene superlattices will be discussed. I will show you the
electronics, such as RF transistors, touch panels, interconnects, and biosensors made of the above-mentioned graphene in the last part of my talk. Device performance will be discussed and compared to the state-of-the art devices with the same functionalities.
If time allows, novel 2D materials based on transition metal dichalcogenides will be informatively involved.
Tailoring of low dimensional materials of bismuth on monolayer epitaxial graphene (P2)
J. C. A. Huang
Department of Physics, National Cheng Kung University, Tainan, Taiwan 701, Taiwan
To improve graphene-based multifunctional devices at nanoscale, a stepwise and controllable fabrication procedure must be elucidated. Here a series of structural transition of bismuth (Bi) adatoms, adsorbed on monolayer epitaxial graphene (MEG) is explored at room temperature by scanning tunneling microscopy (STM). Bi
adatoms undergo a structural transition from one-dimensional (1D) linear structure to two-dimensional (2D) triangular islands and such 2D growth mode is affected by the corrugated substrate. Upon Bi deposition, a little charge occurs and a characteristic peak can be observed in tunneling spectroscopy. When annealed to ~500K, 2D triangular Bi islands aggregate into Bi nanoclusters (NCs) of uniform size. The approaches adopted herein for fabricating and characterizing periodic networks on MEG, which are useful in realizing graphene-based devices at room temperature.
Figure 1 | Mie resonance and absorbance spectra of the Si nanopillar arrays. (a) AFM image of the nanopillar sample. (b) Simulation results compared with experiment; (c,d) Simulated reflectance and absorbance spectra of silicon nanopillar arrays with different diameters. (e) Electric field distributions (|E|/|E0|) of Si nanopillar arrays in (b). (f) Qsca of the Si nanopillar with different effective radius. Mie resonance peaks redshift with the effective radius of nanopillar.
Broadband optical absorption tunable by Mie resonance in silicon nanocone arrays
Z.Y. Wang1, R. J. Zhang1, S. Y. Wang1, 2,*,M. Lu1, L. Y. Chen1,Z. Ye2,C. Z. Wang2 and K. M, Ho2
1Shanghai Engineering Research Center of Ultra-Precision Optical Manufacturing and Department of Optical Science and Engineering, Fudan University, Shanghai, 200433, China
2Ames Laboratory, U. S. Department of Energy and Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, USA
Nanostructures such as nanowire, nanopillar, and nanocone arrays have been proposed as promising antireflection structures due to their great light trapping ability in photovoltaic applications[1-7]. These nanostructure arrays act as an optical antenna while the incident light is coupled to the substrate by the Mie resonance absorption. In this talk, the optical properties of Si nanostructure arrays including nanopillars and nanocones in visible and infrared region were studied by both theoretical calculations and experiments. The results show that the Mie resonance modes can be continuously tuned across a wide range of wavelength by varying the diameter of the nanopillars. However, a Si nanopillar array with uniform diameter exhibits discrete resonance mode, thus can’t achieve a broadband high absorption. On the other hand, the resonance wavelength in Si nanocone arrays can be changed continuously as the diameters of the cross sections increase from the apex to the base. Si nanocone arrays can strongly interact with the incident light in the broadband spectrum and the absorbance is higher than 95% in the wavelength from 300 to 2000 nm. Simulations of reflectance and absorbance for nanopillars arrays reveal a good agreement with experimental results. The simulated results show that the broadband optical absorption from visible to near infrared range of Si nanocone arrays is attributed to Mie resonance, Wood-Rayleigh anomaly effect, and metal impurities introduced in the fabrication process. The absorbance of nanocone arrays can be modulated by its structure parameters, which provides potential applications in optical devices.
1. Chattopadhyay, S. et al. Mat. Sci. Eng. R 69, 1-35 (2010).
2. Spinelli, P., Verschuuren, M. & Polman, A. Nat. Commun. 3, 692 (2012).
3. Hsu, C. M. et al. Adv. Energy Mater. 2, 628-633 (2012).
4. Wang, B. & Leu, P. W. Nanotechnology 23, 194003 (2012).
5. Garnett, E. & Yang, P. Nano Lett. 10, 1082-1087 (2010).
6. Z.Y. Wang, et al. Scientific Reports,5,7810，2015
The anomalous electronic and magnetic properties in black phosphorene (P4)
Jia Yu (賈瑜)
Zhengzhou University (School of Physics and Engineering, International Laboratory for Quantum Functional Materials of Henan, Zhengzhou, China)
By using first-principles calculations within the framework of density functional theory, we investigated the electronic and magnetic properties in black phosphorene. First, we found an anomalous doping effect1 that the electronic properties of phosphorene are drastically modified by the number of valence electrons in dopant atoms. The dopants with even number of valence electrons enable the doped phosphorenes have a metallic feature, while the dopants with odd number of valence electrons keep a semiconducting feature. This even-odd oscillating behavior is attributed to the peculiar tuning lone-electrons in phosphorene as could be seen in figure 1. Second, we have investigated the magnetic structures of zigzag edge phosphorene nanoribbons2 (ZPNRs) with various widths by spin-polarized calculations. The ground state of pristine ZPNRs prefers ferromagnetic order in the same edge but antiferromagnetic order between two opposite edges. The hydrogenated ZPNRs get nonmagnetic semiconductors with a direct band gap, while the O-saturated ZPNRs show magnetic ground states. We also studied the structures of grain boundary3 (GB) and predicted two typical GBs:
A-GB and Z-GB defects. Our results indicate that the grain boundary region is reactive and C or O impurity atoms prefer to be incorporated into the GB region atoms instead of the phosphorene bulk region. Furthermore, both C and O doping inside the grain boundary defects give rise to magnetism in phosphorene. Numerical results also show that relaxed oxygen-saturated diagonal-PNRs4 (O-d-PNRs) realize stable spin-polarized antiferromagnetic (AFM) coupling, and the magnetism is entirely localized at the saturated edges. The AFM state is quite stable under expansive and limited compressive strain. More importantly, not only does the irreversible Wilson transition occur when applying strain, but the nonmagnetic (NM) metal phase (a new ground state) becomes more stable than the AFM state when the compressive strain exceeds −4% as is shown in figure 2.
1. Yu W Y, Zhu Z L, Niu C Y, Li C, Cho J H and Jia Y, Phys. Chem. Chem. Phys. accepted.
2. Zhu Z L, Li C, Yu W Y, Chang D H, Sun Q and Jia Y, Appl. Phys. Lett. 105 113105 (2014) 3. Zhu Z L, Yu W Y, Ren X Y, Sun Q and Jia Y, Europhys. Lett. 109 47003 (2015)
4. Zhang S, Li C, Guo Z X, Cho J H and Jia Y, Nanotechnology accepted.
Figure1. Schematic diagrams of difference charge densities (DOS) of (a) B, (b) C, (c) N and (d) O doped phoshporenes, respectively. Iso surfaces correspond to 0.04 e/Å3
Figure 2. Total energies of the different phases as a function of ε, taking the energy of AFM0 (ε = 0%) as zero.
High-performance Computing Division, NCHC, Taiwan
以視覺化方式設計、串接、執行及管理完整工作流程，達成自動化執行大型模擬 專案並減少可能的人為錯誤，加速數值實驗周期，並縮短研發時程，並使硬體設 施利用更有效率；泛用介面設計（simFactory），提供通用的介面產生器，讓未 具備專業程式開發經驗的一般使用者快速佈建應用程式（simApps），透過自訂 的程式參數模版，快速打造出可以掛載在平台上執行的應用程式，分享結果給相 關的高速計算社群。另外，針對各研究領域間所需之共通模組，開發功能化的高 速計算核心模組（simKernels）並配合學研界實際需求與現況，開發相關應用程 式（simApp），以提升國內大尺度計算模擬的能力與應用廣度及深度，並致力於 將實驗室程式技術商品化。
Quantum Transport of Charge Carriers in Graphene and its Application to Nanoelectronics (I2)
Shu Nakaharai (中払 周)
International Center for Materials Nanoarchitectonics(MANA), National Institute for Materials Science (NIMS), Tsukuba, Japan
Since the first isolation of single layer graphene by mechanical exfoliation, two-dimensional (2D) electron system in graphene has attracted much interest from aspects of both physics and engineering due to its unique band structure. In this presentation, two interesting features of quantum transport in single layer graphene are presented, which are point contact in the quantum Hall regime and defect-induced localization of electrons.
In the quantum Hall regime, half-integer Landau quantization state appears due to the unique gapless band structure, and consequently, in contrast to other semiconductors, there is the 0th Landau level (LL) in which electron-like and hole-like carriers coexist in the same edge channel. When a p-n junction of a macroscopic length is formed by a local top gate biasing, p-type and n-type edge modes coming from different carrier reservoirs merge with each other in the p-n junction, resulting in a perfect edge mode mixing [J. R. Williams, et al., 2007]. In order to investigate the edge mode mixing phenomenon in a mesoscopic quantum dot, a graphene device with a pair of split gates to form a quantum point contact (QPC) was fabricated (Fig. 1(a)). In this device, the global control of the filling states was done by the back gate, and the top gates controlled the local filling states of graphene beneath the top gates. This device enabled open/close operation of the QPC by top-gate biasing in the quantum Hall regime. In the intermediate state of QPC between open and closed configurations, a saddle point of potential was formed at the center of QPC which worked as a quantum dot with two in-coming and two out-going edge modes of 0th LL (Fig. 1(a)). In this configuration, the quantum Hall resistance exhibited an additional plateau (Fig. 1(b)), which was attributed to the mixing of two in-coming edge channels and an equal probability of ejection for two out-going edge channels [S.
Nakaharai, et al., 2011].
Crystalline defects or other resonant scatterers can greatly change the charge carrier conduction property in graphene. Here, we discuss carrier conduction in a single layer graphene which graphene was irradiated with a helium ion beam to generate point defects (Fig. 2(a)). It was found that the conductance decayed exponentially as the defect density increased from 0.1% to 1%. Interestingly, it also exhibited an exponential decay of conductance as the length of irradiated channel increased (Fig.
2(b)), suggesting a strong (Anderson) localization by quantum interference of scattered electrons [S.
Nakaharai et al., ACS Nano 2013]. Due to this localization phenomenon, a transport gap was induced around the Dirac point, and it enabled the carrier conduction control by tuning the Fermi level by gate bias control. We applied the defective graphene as the channel of a transistor, and succeeded in room temperature operation of the transistors which were fabricated in a wafer scale by totally top-down process on a CVD-grown graphene [S. Nakaharai et al., JJAP 2015].
7. J. R. Williams, et al., Science 317, 638 (2007).
8. S. Nakaharai, et al., Phys. Rev. Lett. 107, 036602 (2011).
9. S. Nakaharai, et al., ACS Nano 7, 5694 (2013).
10. S. Nakaharai, et al., Jpn. Jour. Appl. Phys. 54, 04DN06 (2015).
G2 D1 = 2
Figure 1. (a) Experimental configuration of gate-defined graphene QPC device with local filling states and edge channels. The central part forms a quantum dot. (b) The top-gate bias dependence of quantum Hall resistance, RL, RG, where additional plateau was found.
RL: D1-S1 (longitudinal) RG: G1-G2 (transverse)
(b) (a) B
0.2 0 0.2 0.4 0.6 0.8 1 VTG (V)
Figure 2. (a) A schematic of helium ion irradiated graphene in which 1% of carbon atoms were removed. (b) Current versus bias curves of irradiated graphene with different channel length of irradiated region, Lirr. Current decayed exponentially as the Lirr increased.
−1 ID (nA) 0
−1 0 1
Lirr = 0, 5, 10 nm 20 30
基於硫化鎘/硅多界面納米異質結構陣列的色溫可調白光發 射 (I3)
Zhengzhou University (School of Physics and Engineering, International Laboratory for Quantum Functional Materials of Henan, Zhengzhou, China)
以一種具有微米-納米三重層次結構的硅納米孔柱陣列為功能性襯底，採用化學 多相反應法和化學水浴法製備了一種硫化鎘/硅多界面納米異質結構陣列。通過 調製製備條件如化學反應時間、反應溫度、反應液組分及緩衝劑使用、後退火條 件等，實現了對所沉積硫化鎘晶相、平均粒徑及其表面形貌的控制。在實現紅綠 藍三基色光致發光的基礎上，研究了相應的發光機制并製備了電致發光原型器件，
獲得了白光發射并實現了對 LED 器件色溫的有效調製。研究結果對於研製高效 高品質硅基白色光源具有重要的意義。
DNA guided nickel ionS chain memristive system development (I4)
Hsueh-Liang Chu1, Wen-Bin Jian2, Yu-Chang Chen2, 3, Chia-Ching Chang1,4*.
1. Department of Biological Science and Technology, 2. Department of Electrophysics,
and 3National Center of Theoretical Physics, National Chiao Tung University, Hsinchu, Taiwan, 30050; 4. Institute of Physics, Academia Sinica, 128 Academia
Road, Section 2, Nankang, Taipei, Taiwan, 11529.
E-mail: email@example.com ABSTRACT
DNA is a nanowire in nature with multiple base-pairs. Ni ions can be chelated in base-pairs of DNA. The Ni ions can be aligned and form an Ni ion chain (Ni-DNA).
The Ni-DNA exhibits a programmable multi-state memristive system with an added capacitive component. Each Ni ion in Ni-DNA has low and high oxidation state and can be programmed sequentially by applying different polarities and writing time of bias voltage. Therefore, multi-state information can be written, read, and erased on this DNA memristive system. Thus, this Ni-DNA conducting nanowire can be used in combination with other two-terminal devices for a variety of applications in memory as well as n-nary computing. This study also indicates the biomolecules-based self-organized nanostructure can be used as a template for nanodevices fabrication.
Chu, H.-L., Chiu, S.-C., Sung, C.-F., Tseng, W., Chang, Y.-C., Jian, W.-B.*, Chen, Y.-C.*, Yuan, C.-J., Li, H.-Y., Gu, F., Di Ventra, M.; Chang, C.-C.* (2014) Programmable redox state of the nickel ion chain in DNA, Nano Letters 14, 1026-1031.
David W. Lynch
Dept. of Phys., Iowa State University, Iowa, USA
貴金屬材料是重要的光電子材料，所顯示的光學性質在現代光電子材料和 器件等領域獲得了重要應用。採用人工金屬基微納結構，可產生傳統材料所不具 備的各種特殊現象和性能，成為近年來的研究熱點和前沿領域，如負折射、超分 辨成像、超短諧振腔、超隱形等資訊類，以及高效光/電、光熱轉換的新型綠色 能源類器件等，覆蓋了從微波、紅外、可見到紫外的寬廣光譜區，顯示了人工貴 金屬基微納結構在資訊和能源等領域的巨大應用前景。
在研究中克服了貴金屬材料高吸收的困難，製備了一系列入射角精確可控的 貴金屬 Au、Ag、Cu 等樣品，採用不同波長的鐳射，對於光波在貴金屬介面的 傳播特性進行了定量實驗測量，獲得表觀光折射隨入射角和波長變化的定量關係，
由光學常數色散特性所決定的快慢光子等效應。研究結果將有助於人們理解光波 在貴金屬基介面傳播的物理機理，從而為新型微納光電子材料和器件的研製和應 用建立基礎。
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Electrical transport in nanostructured magnetic tunnel junctions with low resistance-area product (I6)
Y. C. Lee1, Lance Horng1, Y. H. Lin2, C. T. Chao1, M. Takahashi3, J. C. Wu1
1National Changhua University of Education, Changhua, 500, Taiwan
2Institute of Physics, National Chiao-Tung University, Hsinchu 300, Taiwan
3Department of Electronic Engineering, Tohoku University, Sendai 980, Japan
Abstract: The magnetic tunnel junction (MTJ) consisting of ultra-thin crystalline MgO sandwiched by two ferromagnetic layers, especially the CoFeB, is the best candidate to achieve high tunneling magnetoresistance (TMR) ratio and low resistance-area (RA) product for the potential applications. Therefore, the thickness, interfacial condition, quality and intrinsic property of the insulating oxide layer have been experimentally and theoretically investigated, in which most of the subjects are studied by analyzing and clarifying the electron transport mechanism. Herein, the electron transport of low-RA CoFeB/MgO/CoFeB based elliptical MTJs of 200×800(samples A and D), 200×400 (sample B), and 300×500(sample C) (unit in nm) have been investigated via the temperature dependent resistance, R(T), measurements. In order to rule out the area effect, all the resistances are multiplied to the corresponding individual area, i.e. RA(T) is used for analysis. Two different categories are discerned: first is with insulator-liked behaviors at both state; and second is with insulator-liked behavior at AP state but metal-liked behavior at P state, especially with an anomalous upturns below 50K. However, all MTJ devices reveal a same temperature dependent MR ratio variation of 0.17 %/K. This tendency indicates the electron transport is mainly dominated by spin-dependent tunneling process accompanied by a slight suppression from spin-independent mechanism. Furthermore, the resistance of one of the devices below 20K has been scrutinized by means of normalizing resistance variation as ΔR/R(20K), where ΔR=R(T)-R(20K). Obviously, ΔR/R(20K) exhibits a T1/2 dependence below 20 K, and this fact is not even affected by a magnetic field of 1 Tesla. This phenomena is corresponding to the model of three-dimensional electron-electron interaction (3-D EEI). Furthermore, highly resistive spin-independent conduction channels (i.e., disordered pinholes) existing inside the MgO barriers are confirmed accordingly.
DFT Study on the Mechanism of Sulfur Poisoning and Coke formation on the Anode of SOFC (I7)
College of Physics and Electronic Engineering, Henan Normal University, Xinxiang, Henan, China
Solid oxide fuel cells (SOFCs) are expected to be a crucial technology in the future power generation[1, 2]. SOFCs offer many desirable advantages compared to other types of fuel cells and conversion devices due to the use of solid electrolytes, lack of moving parts, ability to circumvent precious metal use, high efficiency, low pollution, and fuel flexibility. However, the coke and sulfur poisoning of the Ni/YSZ anode are the two major concerns to limit the application of SOFC.
Trace amounts of H2S presented in biomass generated syngas streams are enough to deactivate the catalyst. Ni catalyzes the formation of carbon deposition at the anode of SOFCs under reducing condition, which would block the active sites and deactivate the Ni catalysts, ultimately destroy the catalyst completely.
Based on the analysis the anode Ni/YSZ structure, we developed three aspects of studies to understand the carbon deposition and sulfur poisoning mechanism as well as their tolerance mechanism.
The three aspects of studies include: 1) the CH4 dissociation, the CH oxidation and the C dimer formation on the Ni based alloy surface[3-5]; 2) the sulfur species adsorption on the the YSZ(111), CeO2(111) surface with first principle thermal dynamics analysis[6-10]; 3) the sulfur species adsorption and diffusion and the carbon formation at the triple phase boundary (TPB) of Ni/YSZ, Ni/Sn alloy /YSZ, Cu/CeO2 and Ni/CeO2 with or without O defects[11-14].
The major conclusions are as following: 1) with the formation of O vacancy at the Ni/YSZ interface, the adsorbed S- would diffuse to the Ni/YSZ interface and is oxidized to S2- and trapped at the oxygen vacancy. Moreover, the trapped sulfur is very difficult to be removed by the fuel (e.g., H2); 2) the TPB model of the Ni/YSZ system with a Sn adatom on the Ni can form a physical barrier and effectively prevent sulfur diffusion to the O vacancy at the interface, and therefore eliminates the sulfur poisoning at the TPB; 3) the CH fragment (the most stable dissociation products of CH4 on Ni catalyst) can easily diffuse and be trapped at the O vacancy of the Ni/YSZ interface. The trapped CH can dissociate to C and H with a much lower dissociation barrier (0.74 eV) as compared with that (1.39 eV) on the pure Ni (111) surface. Therefore, we propose that the carbon deposition may form easily at the interface oxygen vacancy of TPB as compared with that on the pure Ni (111) surface;
4) the diffusion barriers for the process of C-dimer formation (C + C → C dimer) on the bimetallic surface are all higher than that on pure nickel. The results provide a proper explanation on the suppression effects of carbon deposition on the nickel-based alloy catalysts.
We believe our comprehensive studies of the anode Ni/YSZ would be helpful for the experimental researchers to design anode materials with good tolerance of sulfur poisoning and coking.
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Quantum optics in 3-level superconducting artificial atoms (I8)
Department of Physics, National Chung Hsing University, Tainan, Taiwan 402, Taiwan
We experimentally study interactions between two microwave fields mediated by transmon-type 3-level artificial atom. The transmon has good selection rule, preventing one-photon transition, but allowing two-photon transition from ground state(0) to 2nd excited state(2). By pumping a control tone in resonance to the transition between 1st(1) and 2nd excited state(2), we control the one-photon transparency for 0 to 1 transition and two-photon transparency for 0 to 2 transition.
The optical properties of nanoscale thin films studied by spectroscopic ellipsometry (I9)
Rong-Jun Zhang, Song-You Wang, Yu-Xiang Zheng and Liang-Yao Chen Key Laboratory of Micro and Nano Photonic Structures, Ministry of Education,
Department of Optical Science and Engineering, Fudan University, Shanghai 200433, China
In the past decades, it has been discovered and developed entirely new classes of materials and nanostructures, including one-dimensional nanowires and quantum dots of various compositions, polyvalent noble metal nanostructures, superlattices, metamaterials, graphene, and so on. It is drving increasing demand for nanoscale metrology, because of the burgeoning use of nanoscale structured materials in areas from semiconductors, photonics and optoelectronics through biotechnology and chemical sensing. The progress in the current understanding of optical properties of nanomaterials is a very important driving force for developing a variety of applications. Among the various characterization techniques operation at the nanoscale, the versatile nature of spectroscopic ellipsometry(SE) as a functional, nanoscale sensitive, noncontacting, and nondestructive technique, is paving the way for the application of these new nanostructures in a widening field of technologies and for breakthroughs in knowledge of thin film multilayer surfaces, composite and smart materials, and materials engineering at the nanoscale, bypically below 100 nm.
Firstly, the principles of spectroscopic ellipsometry will be introduced, in this lecture. Our ellipsometric characterization of several nanoscale thin films, such as: TiO2, silicon nanocrystalls, BiFeO3 and Pb(Zr0.35Ti0.65)O3, etc., prepared by different methods, are used as examples to discuss various issues related to the optical characterization of nanomaterials, i.e., the surface roughness layer, the detection of buried interfaces, size effects and temperature dependence on their dielectric functions.
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Excellent separation and filtration membrance: Graphene oxide (GO) film (I10)
Department of Physics and Laboratory of Materials Physics, Zhengzhou University, No. 75, Daxue Road, Zhengzhou 450052, China
Graphene oxide (GO) has been demonstrated to be an excellent barrier material for various gases and liquids that holds great promise for applications, such as in separation and filtration as a new kind of ion-exchange membrane.
Hydrogen can permeate faster than CO through the GO film(membrane), therefore, the GO membrane may be used as a selective membrane to separate H2/CO for reforming gas which is used as the fuel of PEMFCs.
The pathway for these molecules is selective structural defects within GO flakes, instead of spacing between GO flakes. Reduction has been shown as an effective way to narrow interlayer spacing in GO membranes but found no obvious gas permeation change.
In our experiment, a RGO membrane with tens of nanometers was put between fuel gas and Pt/C catalyst. Electrochemical measurements were performed with electrochemical workstation. The working electrode is consisted of three parts: RGO membrane, Pt/C catalyst and glassy carbon electrode. Cyclic voltammetry(CV) curves were measured to discuss the electrochemical activity of electrode in electrolyte solution(0.5M H2SO4 aqueous solution). The corresponding CO oxidation reduction peak of the CV curve was reduced significantly after adding RGO membrane, while the Hydrogen redox peaks still exist. Experiments showed that the RGO membrane can effectively filter CO in fuel gas, and improve the anti-CO performance of the electrode in fuel cell and prolong the service life of the Pt/C catalyst.
In addition, some studiers review that the spacing between GO flakes caused the selective permeation. They prepared some kinds of GO films by different methods and different conditions to adjust the spacing between GO flakes in GO membranes, which can be used to separate ions in solution or gas molecules in mixture gas.
For ion permeation, the diverse interactions among anions, cations, and the negatively charged GO membranes are responsible for selective anion permeation through GO membranes. During the ion penetration, electrical potential differences can be generated across drain and source as well as across GO membranes, which can find potential applications in membrane separation, energy generation, ion recognition, and local ion organizing.
Prediction of two dimensional topological insulators in honeycomb structure (I11)
Department of Physics, National Sun Yat-Sen University, Kaohsiung 804, Taiwan
Band topology of strained buckled honeycomb consisted of different elements (IV, V and III-V) as well as those placed on a variety of semiconducting and insulating substrates are systematically investigated using first-principles calculations [1-5]. Topological phase diagrams of these free-standing bilayers are generated to help guide the selection of suitable substrates. The insulating hexagonal-BN is identified as the best candidate substrate material for supporting nontrivial topological insulating phase of bilayer thin films. In addition, some metal induced reconstructed substrates which have the metallic bonding and are semiconducting can be used as templates to grow 2D topological insulators. Furthermore, the bonding between honeycomb structures and substrates can be realized as H-passivation to 2D TIs. This opens up new opportunities for the scientists in the field of surface science.
 Zhi-Quan Huang, Feng-Chuan Chuang*, Chia-Hsiu Hsu, Yu-Tzu Liu, Hua-Rong Chang, Hsin Lin*, and Arun Bansil, Phys. Rev. B 88, 165301 (2013).
 F.C. Chuang*, Chia-Hsiu Hsu, Chia-Yu Chen, Zhi-Quan Huang, Vidvuds Ozolins, Hsin Lin* and Arun Bansil, Appl. Phys. Lett. 102, 022424 (2013).
 Feng-Chuan Chuang*, Liang-Zi Yao, Zhi-Quan Huang, Yu-Tzu Liu, Chia-Hsiu Hsu, Tanmoy Das, Hsin Lin*, and Arun Bansil, Nano Lett. 14, 2505 (2014)
 Zhi-Quan Huang, Chia-Hsiu Hsu, Feng-Chuan Chuang*, Yu-Tzu Liu, Hsin, Lin*, Wan-Sheng Su, Vidvuds Ozoilns, Arun Bansil, New Journal of Physics 16, 105018 (2014).
 Chia-Hsiu Hsu, Zhi-Quan Huang, Feng-Chuan Chuang*, Chien-Cheng, Kuo, Yu-Tzu Liu, Hsin Lin*, Arun Bansil The nontrivial electronic structure of Bi/Sb honeycombs on SiC(0001), New J. Phys. 17, 025005 (2015).
Estimate the number of emitters in a fluorescent nanodiamond (I12)
Tsong-Shin Lim (林宗欣)
Department of Applied Physics, Tunghai University, Taichung, Taiwan
Fluorescent nanodiamond (FND) offers great potential for use as a novel diagnostic agent in biomedicinebecause it is biocompatible, nontoxic, and shows no sign of photobleaching and photoblinking [S.-J. Yu et al., 2005]. The negatively charged nitrogen-vacancy defect (N-V)− center is an active component of FNDs. As the brightness of the FND depends on the number of the color centers it possesses, increasing the content of (N-V)−centers in each particle is highly desirable in view of the biological imaging application of this nanomaterial.
Conventionally, the concentration of (N-V)−center in a bulk diamond sample is estimated by direct absorption spectroscopy [T.-L. Wee et al., 2007]. However, the technique is not sensitive enough to detect (N-V)−center in a single FND particle.
Previous studies have shown that the photons emitted from diamond nanoparticles containing single (N-V)−centers exhibit antibunching behaviors and these particles are useful as single photon sources for quantum cryptography. However, the photon antibunching observed does not reflect directly the actual num number of the fluorophores in the particle.
The deviation becomes more pronounced as the number of the (N-V)−centers increases. In this study, we ues the photon correlation method to obtain the effective numbers of the (N-V)− centers in individual particles. By assuming random dipole orientation of the (N-V)−centers and applying a Monte Carlo method to simulate the probability distribution of the effective number, information about the actual number of these centers in FND is deduced by comparing simulation and measurement. Furthermore, quenching effects, including graphite-shell quenching and impurity quenching, on (N-V)−centers in FNDs can reduce the fluorescence quantum yield and bring about multiexponential decay fluorescence to FNDs.
This causes the number of (N-V)− centers to be underestimated when using the photon correlation method, which presumes identical emitters. Therefore, we further proposes a method that combines time-resolved spectroscopy and photon correlation spectroscopy to modify the number measurement with the photon correlation method.
In addition, a technique based on polarization modulation spectroscopy [T.-S. Lim et al., 2007] is developed to determine quantitatively the number of fluorophores in nanoparticles at the single-molecule level. The technique involves rotation of the polarization of the excitation laser on a millisecond time scale, leading to fluorescence intensity modulation. By taking account of the heterogeneous orientation among the dipoles of the fluorophores and simulating the modulation depth distribution with Monte Carlo calculations, we show that it is possible to deduce the ensemble average and number distribution of the fluorophores.
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Rev. B 75, 165204 (2007).