Motivation

1.5 Motivation

The efficiency of Si-QD solar cell is still not high enough because there are still many problems exist in the SL and ML structure. For SRO-SL, it can’t obtain the uniform QD’s size and high QD’s density simultaneously. For ML structure, such as the thickness of barrier layer (if barrier is too thin, it will lose the ability of confinement), interfacial defects at Si QD/SiO₂ matrix, built-in electrical field [1-26~ 1-28]

, etc. still need to settle.

In this study, we propose the gradient Si/O concentration ML (GSRO-ML) structure. After annealing, Si QDs will precipitate at the high Si/O region within a period layer. We expect that, in this structure, the separation between QDs will be reduced and the density of QDs will be increased but not influence the ability of size control. On the other hand, we adopt the highly phosphorus doping Si target and expect the increased conductivity will improve the electrical properties. We will discuss the characteristics about structural, crystalline, optical and electrical properties in this thesis.

16

Reference

[1-1] B. Chameides,” Statistically Speaking: The Evolution of the Silicon Solar Cell,”

2008

[1-2] M. A. Green, “Third Generation Photovoltaics: Ultra-high Conversion Efficiency at Low Cost,” Prog. Photovolt: Res. Appl., 9, 123-135, 2001

[1-3] G. Conibeer , M. A. Green , R. Corkish , Y. Cho , E. C. Cho, C. W. Jiang, T.

Fangsuwannarak, E. Pink, Y. Huang, T. Puzzer, T. Trupke, B. Richards, A. Shalav, K. L. Lin,

“Silicon Nanostructures for Third Generation Photovoltaic Solar Cells,” Thin Solid Films, 511 – 512, 654 – 662, 2006

[1-4] Y. Kanemitsu, T. Ogawa, K. Shiraishi, and K. Takeda, “Visible PL from Oxidized Si Nanometer-Sized Spheres: Exciton Confinement on A Spherical Shell,” Phys. Rev. B, vol. 48, pp. 4883- 4886, 1993

[1-5] B. H. Bransden and C. J. Joachain, “Introduction to Quantum Mechanics, 2^nd edition,”

2000

[1-6] G. Conibeer, M. A. Green, E.C. Cho, D. Konig, Y. H. Cho, T. Fangsuwannarak, G.

Scardera, E. Pink, Y. Huang, T. Puzzer, S. Huang, D. Song, C. Flynn, S. Park, X. Hao, and D.

Mansfield,” ,” Thin Solid Film, 516, 6748-6756, 2008.

[1-7] M. A. Green, G. Conibeer, D. Konig, E.C. Cho, D. Song, Y. Cho, T. Fangsuwannarak, Y. Huang, G. Scardera, E. Pink, S. Huang, C. Jiang, T. Trupke, R. Corkish, T. Puzzer, “Progress with All Silicon Tandem Cells Based on Silicon Quantum Dots in A Dielectric Matrix.”

Proceedings 21st EU PVSEC, Dresden, 2006

[1-8] C. Feser, J. Lacombe, K. V. Maydell and C. Agert," A Simulation Study Towards A New Concept for Realization of Thin Film Triple Junction Solar Cells Based on Group IV Elements," Prog. Photovolt: Res. Appl., 20, 1, 74-81, 2011

[1-9] E. C. Cho, Y. H. Cho, T. Trupke, R. Corkish, G. Conibeer, and M. A. Green, “Silicon Nanostructures for All-Silicon Tandem Solar Cells,” in Proceedings of the 19th European Photovoltaic Solar Energy Conference and Exhibition, 235, Paris, France, 2004.

[1-10] S. Lombardo and S. U. Campisano, “Electrical And Optical Properties of Semi-insulating Polycrystalline Silicon Thin Films: The Role of Microstructure And Doping,”

Materials Science and Engineering, 17, 8, 281–336, 1996.

[1-11] Y. Cho, E. C. Cho, Y. Huang, T. Trupke, G. Conibeer, and M. A. Green, “Silicon Quantum Dots In SiN_x Matrix for Third Generation Photovoltaics,” in Proceedings of the 20th European Photovoltaic Solar Energy Conference and Exhibition, p. 47, Barcelona, Spain, June 2005

17

[1-12] Y. Kurokawa, S. Miyajima, A. Yamada, and M. Konagai, “Preparation of Nanocrystalline Silicon in Amorphous Silicon Carbide Matrix,” Japanese Journal of Applied Physics, 45, 40, L1064–L1066, 2006.

[1-13] D. Song, E. C. Cho, Y. H. Cho, G. Conibeer, Y. Huang, S. Huang, M. A. Green,

“Evolution of Si (and SiC) nanocrystal precipitation in SiC matrix,” Thin Solid Films, 516, 12, 30, 3824–3830, 2008

[1-14] H. Takagi, H. Ogawa, Y. Yamazaki, A. Ishizaki, and T. Nakagiri,” Quantum Size Effects on Photoluminescence in Ultrafine Si Particles,” Appl. Phys. Lett. 56, 2379, 1990 [1-15] M. Ehbrecht, H. Ferkel, F. Huisken, L. Holz, Y. N. Polivanov, V. V. Smirnov, O. M.

Stelmakh, and R. Schmidt,” Deposition And Analysis of Silicon Clusters Generated By Laser‐Induced Gas Phase Reaction,” J. Appl. Phys. 78, 5302, 1995

[1-16] T. S. Iwayama, S. Nakao, and K. Saitoh,” Visible Photoluminescence in Si⁺‐implanted Thermal Oxide Films on Crystalline Si,” Appl. Phys. Lett. 65, 1814, 1994 [1-17] G.A. Kachurin, S.G. Cherkova, V.A. Volodin, V.G. Kesler, A.K. Gutakovsky, A.G.

Cherkov, A.V. Bublikov, and D.I. Tetelbaum,” Implantation of P Ions in SiO2 Layers with Embedded Si Nanocrystals,” Phys. Res. B, 222(3-4), 497–504, 2004

[1-18] G. Belomoin, J. Therrien, A. Smith, S. Rao, and R. Twesten, S. Chaieb, M. H. Nayfeh, L. Wagner and L. Mitas," Observation of A Magic Discrete Family of Ultrabright Si Nanoparticles," Appl. Phys. Lett., 80, 841, 2002.

[1-19] A. Nakajima, Y. Sugita, K. Kawamura, H. Tomita, and N. Yokoyama,” Si Quantum Dot Formation with Low-Pressure Chemical Vapor Deposition,” Jpn. J. Appl. Phys., 35, L189, 1996

[1-20] F. Iacona, G. Franzò, and C. Spinella,” Correlation between Luminescence and Structural Properties of Si Nanocrystals,” J. Appl. Phys. 87, 1295, 2000

[1-21] A. A. Gonza´lez-Ferna´ndez, J. Juvert, Alfredo Morales-Sa´nchez, Jorge Barreto, M.

Aceves-Mijares, and C. Dominguez,” Comparison of Electrical and Electro-Optical Characteristics of Light-Emitting Capacitors Based on Silicon-Rich Si-Oxide Fabricated By Plasma-Enhanced Chemical Vapor Deposition and Ion Implantation,” J. Appl. Phys. 111, 053109, 2002

[1-22] E. Werwa, A. A. Seraphin, L. A. Chiu, C. Zhou, and K. D. Kolenbrander,” Synthesis And Processing of Silicon Nanocrystallites Using A Pulsed Laser Ablation Supersonic Expansion Method,” Appl. Phys. Lett. 64, 1821, 1994

[1-23] E. Mota-Pineda, M. Meléndez-Lira, M. Zapata-Torres, P. del Angel, A.

Pérez-Centeno, S. Jiménez-Sandoval, and M. A. Santana-Aranda,” Photoluminescence of As-Grown And Thermal Annealed SiOx/Si-Nanocrystals Heterolayers Grown by Reactive RF Sputtering,” J. Appl. Phys. 108, 094323, 2010

[1-24] M. Zacharias, J. Heitmann, R. Scholz, U. Kahler, M. Schmidt, and J. Bl¨asing,

18

“Size-Controlled Highly Luminescent Silicon Nanocrystals: A SiO/SiO2 Superlattice Approach,” Appl. Phys. Lett., 80, 4, 661–663, 2002.

[1-25] L. L. Chang, L. Esaki, W. E. Howard, and R. Ludeke, “The Growth of A GaAs-GaAlAs Superlattice,” J. Vac. Sci. Technol, 10, 1, 11–16, 1973.

[1-26] X. J. Hao, E. C.Cho, C. Flynn, Y. S. Shen, S. C. Park, G. Conibeer, and M. A. Green,”

Synthesis and Characterization of Boron-Doped Si Quantum Dots for All-Si Quantum Dot Tandem Solar Cells,” Sol. Energy Mater. Sol. Cells, 93, 273-279, 2009

[1-27] X. J. Hao, E. C. Cho, G. Scardera, E. Bellet-Amalric, D. Bellet, Y. S. Shen, S. Huang, Y. D. Huang, G. Conibeer, and M. A. Green,” Effects of Phosphorus Doping on Structural and Optical Properties of Silicon Nanocrystals in A SiO2 Matrix,” Thin Solid Films, 517, 5646, 2009

[1-28] X. J. Hao, E. C. Cho, G. Scardera, Y. S. Shen, E. Bellet-Amalric, D. Bellet, G.

Conibeer, and M. A. Green,” Phosphorus-Doped Silicon Quantum Dots for All-Silicon Quantum Dot Tandem Solar Cells,” Sol. Energy Mater. Sol. Cells, 93, 1524, 2009

[1-29] S. Park , E. C. Cho, D. Song, G. Conibeer, M. A. Green, “N-Type Silicon Quantum Dots and P-Type Crystalline Silicon Heteroface Solar Cells.” Sol. Energy Mater. Sol. Cells, 93, 684–690, 2009

[1-30] S. H. Hong, Y. S. Kim, W. Lee, Y. H. Kim, J. Y. Song, J. S. Jang, J. H. Park, S. H.

Choi and K. J. Kim,” Active Doping of B in Silicon Nanostructures and Development of A Si Quantum Dot Solar Cell,” Nanotechnology, 22, 425203, 2011

[1-31] I. Perez-Wurf, X. Hao, A. Gentle, D. Kim, G. Conibeer, and M. A. Green," Si Nanocrystal p-i-n Diodes Fabricated on Quartz Substrates for Third Generation Solar Cell Applications," Appl. Phys. Lett., 95, 153506, 2009

19