τσ+
τσ−
Fig. 7 Lifetime as a function of magnetic field. The squares represent σ+ and circles stand for σ– circular polarization.
1.80 1.84 1.88 1.92 1.96
1.894 eV
PL Intensity (a.u.)
Photon energy (eV)
0 ns 2 ns 4 ns 6 ns 8 ns 10 ns 12 ns 14ns 16 ns 18 ns 20 ns
1.908 eV
Fig. 8 The time-resolved PL spectra of ZnMnTe MQDs at various time.
1.84 1.88 1.92 1.96
PL Intensity (a.u.)
Photon energy (eV)
1.905 eV 0 ns
2 ns 4 ns 6 ns 8 ns 10 ns 12 ns 14ns 16 ns 18 ns 20 ns
1.910 eV
Fig. 9 Time-resolved PL spectra of ZnTe MQDs at various time.
-5 0 5 10 15 20 25 30 35 40 1.885
1.890 1.895 1.900 1.905
Phton energy (eV)
Time (ns)
10 K 25 K 50 K 75 K 100 K
Fig. 10 Time dependent PL peak energy of ZnMnTe MQDs at 10 to 100 K.
0 20 40 60 80 100
Fig. 11 Temperature dependence of the magnetic-polaron formation time (right) and magnetic-polaron binding energy (left).
Chapter 6
ZnTe/ZnMnSe quantum dots
In this chapter, optical properties of type-II diluted magnetic semiconductor (DMS) ZnTe/ZnMnSe quantum dots (QDs) were investigated by low temperature, time-resolved and magneto photoluminescence (PL) spectroscopy. The magneto-optical measurement demonstrates a magnetic-induced degree of circular polarization in the PL spectra. In addition, the magnetic polarons formation was also observed in this system.
The samples studied in this chapter were grown on GaAs (100) substrates by a Vecco Applied EPI 620 molecular beam epitaxy (MBE) system. Solid sources Zn, Te, Mn and Se were used for the growth of self-assembled ZnTe QDs and Zn(Mn)Se buffers. The growth rate for ZnMnSe buffer layer is 0.04 nm/s, and the growth rate for the ZnTe QDs is 0.03 nm/s. The effusion cell temperatures of Zn, Mn, Se, and Te are 294, 695, 178, and 310 oC, respectively. Prior to the growth procedure, GaAs (100) substrate was etched in a H2O2 : NH4OH : H2O (1:5:50) solution. The substrate temperatures were set at 300 ℃. The growth process started with several mono-layers (MLs) of ZnSe by migration enhanced epitaxy, followed by a ZnSe buffer layer of 50 nm by conventional MBE. The 50 nm ZnMnSe buffer layer growth follows the
growth of ZnSe buffer layer. Immediately after the deposition of ZnMnSe buffer layer, the alternating supply method of ZnTe growth was performed. The average roughness of the ZnMnSe buffer layer was approximately 0.5 nm, indicating that the surface of ZnMnSe buffer layer is flat. The average coverage of ZnTe for samples one to five was 1.8, 2.2, 2.4, 2.7 and 3.0 MLs, respectively. The details of growth parameters are listed in Table 2.4. A 50 nm ZnMnSe capping layer was grown on the QDs for optical measurements. The AFM image of the 2.7 ML ZnTe/ZnMnSe QDs was shown in Fig.
1. The average diameter of the QDs is about 60 nm and average height is 4 to 5 nm.
The dot density is estimated approximately 109-1010 cm-2.
The low temperature PL spectra of ZnTe/ZnMnSe QDs with different coverage were showed in Fig. 2. The sharp peak near 2.797 eV is attributed to the near band edge emission of the ZnMnSe matrix. There are mainly two emission bands observed in the PL spectra at the spectral region from 1.9 eV to 2.4 eV. The lower-energy emission band is due to QD recombination because the corresponding PL peak energy is more sensitive to the change of coverage, compared to that of higher-energy emission band (~ 2.30 eV). The emission energies are lower than that of the ZnTe epilayer (2.38 eV at 10 K) which implies a type-II band alignment for ZnTe QDs grown in the ZnMnSe matrix. The redshift in energy with the increasing ZnTe
ZnTe QDs. The broad peak around 2.30 eV is due to the emission from wetting layer, which has been described in chapter 4 and 5. The peak energy as a function of ZnTe coverage was inserted in Fig. 2. Two different redshift slopes are found for the coverage dependence of PL peak energy. The slope change of red-shift indicates that the critical coverage for QDs formation is about 2.4 MLs. It is also corroborated by the study of RHEED patterns.
Figure 3 (a) shows the PL spectra of σ+ (dash line) and σ- (solid line) polarization of a 2.7 ML QDs at B = 0. The circular polarization rate P = (I+ - I-)/(I+ + I-) is zero in this case. Where, I+ and I- are the integrated PL intensity of σ+ and σ- circular polarization, respectively. In Fig. 3 (b), the PL spectra of σ+ and σ- polarization at B = 4 T were shown. The σ+ polarization spectrum dominates the emission, non-zero circular polarization rate is apparent. In Fig. 4, the polarization as a function of magnetic field intensity B is plotted. The polarization is a Brillouin function of magnetic field intensity B. It increases more or less linearly at low B and saturates at high B. At B above 4 T, the polarization reaches 76 %.
In Fig.4, the solid line is a fitting curve for the magnetic field dependence of circular polarization P by using equation Eq. (5-3). The best fit to the data yields
g B
kT
μ = 1.15±0.05 (Tesla-1) and τS /τR = 0.31±0.01. This indicates that the spin
relaxation time is about 3 times shorter than the exciton recombination time.
In order to determineτR, the decay profiles of time-resolved PL were measured.
The decay profile fitted by the Kohlrausch’s stretching exponential function:
( ) 0exp{ ( / ) }
PL PL
I t =I − t τ β ,
where τPL is the exciton radiative recombination time (τR), and β is the stretching exponential. A very long decay time of about 112 ns due to the type II band alignment induced slow exciton recombination. The spin relaxation time is then estimated to be about 35 ns.
In Fig.5, the polarizations as a function of magnetic field intensity B of ZnMnTe 2.6 MLs SQD, 2.6 MLs MQD and ZnTe/ZnMnSe 2.7 MLs SQD are shown. We found that the polarization of ZnMnTe 2.6 MLs SQD saturated at 60 %, it is smaller than the polarizations of ZnTe/ZnMnSe 2.7 MLs SQD and ZnMnTe 2.6 MLs MQD.
The polarizations of ZnMnTe 2.6 MLs MQD and ZnTe/ZnMnSe 2.7 MLs SQD saturated at 80 %. Based on the fact that the PL lifetime (10 ns) of ZnMnTe 2.6 MLs SQD was shorter than the PL lifetime of 2.6 MLs MQD and ZnTe/ZnMnSe 2.7 MLs SQD, it implies that not all the carriers were release to the lower state before the recombination in ZnMnTe 2.6 MLs SQD. Therefore the saturation polarization in ZnMnTe 2.6 MLs SQD is smallest.
In Fig. 6, we show the evolution of the relative recombination energy for 2.7
to 20 ns. This redshift is due to the formation of MPs. The transient redshift of the PL signal was fitted by equation 5-6. The best fit yields exciton MP formation time of 7 ns and polaron binding energy of 17 meV.
The MP binding energy and MP formation time of ZnMnTe 2.6 MLs SQD, 2.6 MLs MQD and ZnTe/ZnMnSe 2.7 MLs SQD were listed in table 6.1. All the values of polaron binding energy and MP formation time in three samples are almost the same. All the samples in table 6.1 have type II band aligned, which exhibit longer recombination lifetime than MP formation time. In ZnMnTe QDs system the hole spin aligns the randomly oriented Mn spins, but in ZnTe/ZnMnSe QD system the electron spin aligns the randomly oriented Mn spins. It implies that the efficiency for the electron and hole spins to align the Mn spin are about the same.
The PL efficiency of ZnMnTe/ZnSe QDs and ZnTe/ZnMnSe QDs were dominated by the localized holes in the QDs. In ZnMnTe/ZnSe QDs, the Mn2+ could localize holes in ZnMnTe layers resulting a decrease in the QDs PL efficiency. In ZnTe/ZMnSe QDs, the Mn2+ localized holes or electons in ZnMnSe, it is unlikely to influence the QDs PL efficiency. Compared with the PL intensity of ZnMnTe/ZnSe MQDs, the PL intensity of ZnTe/ZnMnSe SQDs is stronger.
In conclusion, the magnetic field dependence of PL circular polarization degree follows the Brillouin function and evidences the Mn magnetism in ZnTe/ZnMnSe
QDs. The magnetic field dependence of PL circular polarization degree shows the long spin relaxation time of about 35 ns. The magnetic polaron formation was observed in low temperature.
Fig. 1 AFM image of 2.7 MLs ZnTe/ZnMnSe QDs.
Fig. 2 Low temperature PL spectra of ZnTe QDs with different coverages. The inset shows the PL peak energy of QD as a function of ZnTe coverage. The solid line is just a guide for eyes.
1.7 1.8 1.9 2.0
(b)
B = 4T P = 76 %
σ−
Magneto-PL Intensity (a.u.)
Photon energy (eV) σ+
B = 0T P = 0
ZnTe/ZnMnSe 2.7 ML
(a)
Fig. 3 PL spectra with σ+ (solid line) and σ– (dashed line) circular polarization of 2.7 ML at B = 0 T and B = 5 T.
0 1 2 3 4 5 6 0
20 40 60 80
Polarization (%)
Magnetic field (T)
Fig. 4 Plot of circular polarization as a function of magnetic field at 10K (circle).
0 1 2 3 4 5 6
Fig. 5 The magnetic field dependent circular polarization of ZnMnTe/ZnSe 2.6 MLs SQDs, ZnMnTe/ZnSe 2.6 MLs and ZnTe/ZnMnSe 2.7MLs SQDs.
1.82 1.84 1.86 1.88 1.90 1.92 1.94
Chapter 7 Conclusion
II-VI semiconductor quantum wells and quantum dots with type II band alignment were grown on GaAs(001) substrates using an EPI620 MBE system. For the ZnSe0.8Te0.2/ZnSe multiple quantum well (MQW), the nature of type II recombination was confirmed by excitation power dependent photoluminescence. An extraordinary long lifetime was detected in the MQW systems. Also, the binding energy of the indirect excitons is determined as 12 meV for the thinnest sample. The indirect-exciton recombination rate enhances under a high excitation density, based on the band-bending model. The effect plays an important role in the observed high emission efficiency.
The PL results, reflection high-energy electron diffraction pattern, and AFM images showed that the critical thickness for dot formation of Stranski-Krastanov ZnTe/ZnSe QDs is around 2.5 MLs. The initial decrease then increase with temperature for the full width at half maximum (FWHM) of PL is attributed to the hole thermal escape from the smaller QDs then transfer and re-capture to the neighboring-larger QDs. The non-mono-exponential decay profiles reflect the processes of carrier transfer and recapture. We show that the Kohlrausch’s stretching
exponential well fits the decay profiles of ZnTe/ZnSe QDs. The lifetime decreases with the coverage thickness and decreases to values less than 100 ns. The stretching exponent β also drops as the coverage above 2.5 ML. For the 0-D case, the formation of QDs results in an increase in numbers of recombination centers and a decrease in the traveling time.
The ZnMnTe QD samples were grown by first exposed Mn flux for a few seconds, and then Zn+Te flux. The magnetic field dependence of PL circular polarization degree follows the Brillouin function and evidences the Mn magnetism in ZnMnTe QDs. In combination with the time-resolved PL measurement, it also shows the long spin relaxation time of about 23 ns. Furthermore, the magnetic polaron persists up to 100 K and the formation energy is roughly independent of temperature.
Finally, the PL results showed that the critical thickness for dot formation of ZnTe/ZnMnSe QDs is around 2.4 MLs. The magnetic field dependence of PL circular polarization degree follows the Brillouin function and evidences the Mn magnetism in ZnTe/ZnMnSe QDs. The magnetic field dependence of PL circular polarization degree shows the long spin relaxation time of about 35 ns. The magnetic polaron formation was also observed in ZnTe/ZnMnSe QDs.
Reference
1. D. Alonso-Alvarez, B. Alen, J. M. Garcia, and J. M. Ripalda, Appl. Phys. Lett. 91, 263103 (2007).
2. M. Geller, C. Kapteyn, L. Muller-Kirsch, R. Heitz, and D. Bimberg, Appl. Phys.
Lett. 82, 2706 (2003).
3. R. B. Laghumavarapu, A. Moscho, A. Khoshakhlagh, M. El-Emawy, L. F. Lester, and D. L. Huffaker, Appl. Phys. Lett. 90, 173125 (2007).
4. U. E. H. Laheld, F. B. Pederson, and P. C. Hemmer: Phys. Rev. B 52, 2697 (1995).
5. E. Ribeiro, A. O. Govorov, W. Carvalho, Jr., and G. Medeiros-Ribeiro, Phys. Rev.
Lett. 92, 126402 (2004).
6. G. F. Neumark, R. M. Park, and J. M. Depuydt, Phys. Today 47(6), 29 (1994).
7. C. S. Yang, D. Y. Hong, C. Y. Lin, W. C. Chou, C. S. Ro, W. Y. Uen, W. H. Lan, and S. L. Tu, J. Appl. Phys. 83, 2555 (1998).
8. Y. Gu, Igor L. Kuskovsky, M. van der Voort, G. F. Neumark, X. Zhou, and M. C.
Tamargo, Phys. Rev. B 71, 045340 (2005).
9. D. Lee, A. Mysyrowicz, A. V. Nurmikko, and B. J. Fitzpatrick, Phys. Rev. Lett. 58, 1475 (1987).
10. A. Muller, P. Bianucci, C. Piermarocchi, M. Fornari, I. C. Robin, R. André, and C.
11. H. C. Lee, T. Abe, Z. M. Aung, M. Adachi, T. Shirai, H. Yamada, S. Kuroda, K.
Maruyama, H. Kasada, and K. Ando, J. Cryst. Growth 214/215, 1096 (2000).
12. K. Suzuki, U. Neukirch, J. Gutowski, N. Takojima, T. Sawada, and K. Imai, J.
Cryst. Growth 184/185, 882 (1998)
13. G. T. Einevoll, D. S. Citrin, and Y. C. Chang, Phys. Rev. B 44, 8068 (1991).
14. C. S. Yang, C. C. Cheng, M. C. Kuo, P. Y. Tseng, J. L. Shen, J. Lee, W. C. Chou, S.
Jeng, C. Y. Lai, T. M. Hsu, and J. J. Chyi, Thin Solid Films 429, 243 (2003)
15. A. Reznitsky, S. Permogorov, S. Verbin, A. Naumov, Yu. Korostelin, V.
Novozhilov, and S. Prokov’ev, Solid State Comm. 52, 13 (1984)
16. R. I. Dzhioev, V. L. Korenev, I. A. Merkulov, B. P. Zakharchenya, D. Gammon, Al.
L. Efros, and D. S. Katzer, Phys. Rev. Lett. 88, 256801 (2002)
17. H. Gotoh, H. Ando, T. Sogawa, H. Kamada, T. Kagawa, and H. Iwamura, J. Appl.
Phys. 87, 3394 (2000)
18. M. Z. Maialle, E. A. de Andrada e Silva, and L. J. Sham, Phys. Rev. B 47, 15776 (1993)
19. M. Feucker, R. Seguin, S. Rodt, A. Hoffmann, and D. Bimberg, Appl. Phys. Lett.
92, 063116 (2008).
20. J. Tatebayashi, B. L. Liang, R. B. Laghumavarapu, D. A. Bussian, H. Htoon, V.
295704 (2008).
21. J. Tatebayashi, A. Khoshakhlagh, S. H. Huang, G. Balakrishnan, L. R. Dawson, D.
L. Huffaker, D. A. Bussian, H. Htoon, and V. Klimov, Appl. Phys. Lett. 90, 261115 (2007).
22. V. G. Talalaev, J. W. Tomm, N. D. Zakharov, P. Werner, U. Gösele, B. V. Novikov, A. S. Sokolov, Y. B. Samsonenko, V. A. Egorov, and G. E. Cirlin, Appl. Phys. Lett.
93, 031105 (2008).
23. J. H. Park, D. G. Choi, T. K. Lee, Eunsoon Oh, Sanghoon Lee, and J. K. Furdyna, Appl. Phys. Lett. 90, 201916 (2008).
24. C.-K. Sun, G. Wang, J. E. Bowers, B. Brar, H.-R. Blank, H. Kroemer, and M. H.
Pilkuhn, Appl. Phys. Lett. 68, 1543 (1996).
25. Haiping Yu, Sam Lycett, Christine Roberts, and Ray Murray, Appl. Phys. Lett. 69, 4087 (1996).
26. R. Hostein, A. Michon, G. Beaudoin, N. Gogneau, G. Patriache, J.-Y. Marzin, I.
Robert-Philip, I. Sagnes, and A. Beveratosa, Appl. Phys. Lett. 93, 073106 (2008).
27. Y. C. Lin, W. C. Chou, W. C. Fan, J. T. Ku, F. K. Ke, W. J. Wang, S. L. Yang, W.
K. Chen, W. H. Chang, and C. H. Chia, Appl. Phys. Lett. 93, 241909 (2008).
28. B. Sturman, E. Podivilov and M. Gorkunov, Phys. Rev. Lett. 91, 176602 (2003).
29. C. S. Yang, Y. J. Lai, W. C. Chou, W. K. Chen, M. C. Lee, M. C. Kuo, J. Lee, J. L.
Shen, D. J. Jang, and Y. C. Cheng, J. Appl. Phys. 97, 033514 (2005).
30. J. Seufert, G. Bacher, M. Scheibner, A. Forchel, S. Lee, M. Dobrowolska, and J. K.
Furdyna, Phys. Rev. Lett. 88, 027402 (2001).
31. S. Mackowski, T. Gurung, T. A. Nguyen, H. E. Jackson, L. M. Smith, G.
Karczewski, J. Kossut, Appl. Phys. Lett. 84 3337 (2004).
32. Y. Leger, L. Besombes, L. Maingault, D. Ferrand, and H. Mariette, Phys. Rev. Lett.
95, 047403 (2005).
33. C. Gould, A. Slobodskyy, D. Supp, T. Slobodskyy, P. Grabs, P. Hawrylak, F. Qu, G.
Schmidt, and L. W. Molenkamp, Phys. Rev. Lett. 97, 017202 (2006).
34. Y. Leger, L. Besombes, J. Fernández-Rossier, L. Maingault, and H. Mariette, Phys.
Rev. Lett. 97, 107401 (2006).
35. R. Beaulac, P. I. Archer, S. T. Oschsenbein, and D. R. Gamelin, Adv. Func. Mater.
18, 3873 (2008).
36. J. K. Furdyna, J. Appl. Phys. 64, R29 (1988).
37. I. Zutic, J. Fabian, and S. Das Sarma, Rev. Mod. Phys. 76, 323 (2004).
38. J. Fernandez-Rossier and L. Brey, Phys. Rev. Lett. 93, 117201 (2004); A. O.
Govorov, Phys. Rev. B 72, 075359 (2005); R. M. Abolfath, P. Hawrylak, and I.
Zutic, Phys. Rev. Lett. 98, 207203 (2007).
40. T. Dietl and J. Spalek, Phys. Rev. Lett. 48, 355 (1982); Phys. Rev. B 28, 1548 (1983).
41. P. A. Wolff, in Semiconductors and Semimetals, ed. by J. K. Furdyna and J.
Kossut (Academic Press, New York, 1988), Vol. 25, p. 413.
42. D. Heiman, P. Wolff, and J. Warnock, Phys. Rev. B 27, 4848 (1983).
43. R. Heitz, A. Kalburge, Q. Xie, M. Grundmann, P. Chen, A. Hoffmann, A.
Madhukar, and D. Bimberg, Phys. Rev. B 57, 9050 (1998).
44. Q. Fu, D. Lee, A. V. Nurmikko, L. A. Kolodziejski, and R. L. Gunshor, Phys. Rev.
B 39, 3173 (1989).
45. A. A. Maksimov, S. V. Zaitsev, I. I. Tartakovskii, V. D. Kulakovskii, D. R.
Yakovlev, W. Ossau, M. Keim, G. Reuscher, A. Waag, and G. Landwehr, Appl.
Phys. Lett. 75, 1231 (1999).
46. N. N. Ledentsov, J. Bohrer, M. Beer, F. Heinrichsdorff, M. Grudmann, D.
Bimberg, S. V. Ivanov, B. Ya, S.V. Meltser, I. N. Shaposhnikov, N. N. Yassievich, P.S. Faleev, Kop’ev, Zh. I. Alferov, Phys. Rev. B 52 14058 (1995).
47. M. Gurioli, A. Vinattieri, M. Colocci, C. Deparis, J. Massies, G. Neu, A. Bosacchi, and S. Franchi, Phys. Rev. B 44, 3115 (1991).
48. Y. J. Lai, Y. C. Lin, C. B. Fu, C. S. Yang, C. H. Chia, D. S. Chuu, W. K. Chen, M.
49. H. S. Lee, J. Y. Lee, and T. W. Kim, J. Cryst. Growth 258, 256 (2003).
50. Johnson Lee, Emil S. Koteles, and M. O. Vassell, Phys. Rev. B 33, 5512 (1986).
51. C. Gourdon, and P. Lavallard, phys. Stat. sol. (b) 153 641 (1989).
52. C. S. Kim, M. Kim, S. Lee, J. Kossut, J. K. Furdyna, and M. Dobrowolska, J.
Cryst. Growth 214/215, 395 (2000).
53. E. Oh, K. J. Yee, S. M. Soh, J. U. Lee, J. C. Woo, H. S. Jeon, D. S. Kim, S. Lee, J.
K. Furdyna, H. C. Ri, H. S. Chany, S. H. Park, Appl. Phys. Lett. 83 4604 (2003).
54. G. Bacher, A. A. Maksimov, H. Schomig, V. D. Kulakovskii, M. K. Welsch, A.
Forchel, P. S. Dorozhkin, A. V. Chernenko, S. Lee, M. Doborowolska, and J. K.
Furdyna, Phys. Rev. Lett. 89, 127201 (2002).
55. V. V. Rossin, F. Henneberger, and J. Puls, Phys. Rev. B 53, 16444 (1996).
56. J.H. Harris and A.V. Nurmikko, Phys. Rev. Lett. 51, 147 (1983).
57. R. Beaulac, L. Schneider, P. I. Archer, G. Bacher, and D. R. Gamelin, Science 325 973 (2009).
發表著作(Publications) (A)期刊論文 (Referred Papers)：
1. Y. C. Lin, H. L. Chung, J. T. Ku, C. Y. Chen, K. F. Chien, W. C. Fan, L. Lee, J. I.
Chyi, W. C. Chou, W. H. Chang, and W. K. Chen, “Optical characterization of isoeletronic ZnSe1-xOx semiconductors”, J. Cryst. Growth 323, 122 (2011) 2. W. C. Fan, J. T. Ku, W. C. Chou, W. K. Chen, W. H. Chang, C. S. Yang, C. H.
Chia, “Magneto-optical properties of ZnMnTe/ZnSe quantum dots”, J. Cryst.
Growth 323, 380 (2011)
3. C. H. Chia, W. C. Fan, Y. C. Lin, and W. C. Chou, “Radiative recombination of indirect exciton in type-II ZnSeTe/ZnSe multiple quantum wells”, J.
Luminescence 131, 956 (2011)
4. I. R. Seller, R. Oszwaldowski, V. R. Whiteside, M. Eginligil, A. Petrou, I. Zutic, W. C. Chou, W. C. Fan, A. G. Petukhov, S. J. Kim, A. N. Cartwright, and B. D.
McCombe, “Robust magnetic polarons in type-II (Zn, Mn)Te/ZnSe magnetic quantum dots”, Phys. Rev. B 82, 195320 (2010)
5. L. Lee, W. C. Fan, J. T. Ku, W. H. Chang, W. K. Chen, W. C. Chou, C. H. Ko, C.
H. Wu, Y. R. Lin, C. H. Wann, C. W. Hsu, Y. F. Chen, and Y. K. Su,
“Cathodoluminescence studies of GaAs nano-wires grown on shallow-trench-patterned Si”, Nanotechnology 21, 465701 2010
6. C. H. Chia, Y. J. Lai, W. L. Hsu, T. C. Han, J. W. Chiuo, Y. M. Hu, Y. C. Lin, W. C.
Fan, W. C. Chou, “Biexciton emission from sol-gel ZnMgO nanopowders”, Appl.
Phys. Lett. 96, 191902 (2010)
7. J. W. Chou, K. C. Lin, Y. T. Tang, F. K. Hsueh, Y. J. Lee, C. W. Luo, Y. N. Chen, C. T. Yuan, H. C. Shih, W. C. Fan, M. C. Lin, W. C. Chou, and D. S. Chuu,
“Fluorescence signals of quantum dots influenced by spatially controlled arrays structures”, Nanotechnology 20, 415201 (2009)
8. J. W. Chou, K. C. Lin, Y. J. Lee, C. T. Yuan, F. K. Hsueh, H. C. Shih, W. C. Fan, C. W. Luo, M. C. Lin, W. C. Chou, and D. S. Chuu, “Observation of localized surface plasmons in spatially controlled array structures”, Nanotechnology 20, 305202 (2009)
9. Y. C. Lin, W. C. Chou, W. C. Fan, J. T. Ku, F. K. Ke, W. J. Wang, S. L. Yang, W.
K. Chen, W. H. Chang, and C. H. Chia, “Time-resolved photoluminescence of isoelectronic traps in ZnSe1-xTex semiconductor alloys”, Appl. Phys. Lett. 93, 241909 (2008)
10. Y. C. Lin, W. C. Fan, C. H. Chia, F. K. Ke, S. L. Yang, D. S. Chuu, M. C. Lee, W.
K. Chen, W. H. Chang, W. C. Chou, J. S. Hsu, and J. L. Shen, “Pressure-induced
013503 (2008)
11. I. R. Seller, V. R. Whiteside, A. O. Govorov, W. C. Fan, W. C. Chou, I. Khan, A.
Petrou, B. D. McCombe, “Coherent Aharonov-Bohm oscillations in type-II (Zn,Mn)/Te/ZnSe quantum dots”, Phys. Rev. B 77, 241302 (2008)
12. Y. C. Lin, C. H. Chiu, W. C. Fan, C. H. Chia, S. L. Yang, D. S. Chuu, M. C. Lee, W. K. Chen, W. H. Chang, and W. C. Chou, “Raman scattering of
longitudinal-optical-phonon-plasmon coupling in Cl-doped ZnSe under high pressure”, J. Appl. Phys. 102, 123510 (2007)
13. Y. C. Lin, C. H. Chiu, W. C. Fan, S. L. Yang, D. S. Chuu, and W. C. Chou,
“Pressure-induced Raman scattering and photoluminescence of Zn1-xCdxSe epilayers”, J. Appl. Phys. 101, 075307 (2007)
14. M. C. Kuo, J. S. Hsu, J. L. Shen, K. C. Chiu, W. C. Fan, Y. C. Lin, C. H. Chia, W.
C. Chou, M. Yasar, R. Mallory, A. Petrou, and H. Luo, “Photoluminescence studies of type-II diluted magnetic semiconductor ZnMnTe/ZnSe quantum dots”, Appl. Phys. Lett. 89, 263111 (2006)
(B)研討會論文：
1. L. Lee, W. C. Ke, W. C. Fan, J. T. Ku, W. H. Chang, W. K. Chen and W. C. Chou,
“Optical characterization of semiconductor microstructures using cathodoluminescence”, 28th Symposium on Spectroscopic Technologies and Surface Sciences, July, 2009