臺灣博碩士論文加值系統

In this thesis we report two studies include optical properties of CdTe/CdSe core-shell type II quantum dots and time-resolved photoluminescence (PL) in CdSe/ZnS core-shell type I quantum dots. The former and later results are obtained from photoluminescence, photoluminescence excitation measurement and time-resolved PL measurement respectively. Quite interesting results provide useful results for the enhancement of our understanding and application in these materials.

I.Optical properties of CdTe/CdSe core-shell type II quantum dots
We report investigation of optical properties of type-II CdTe/CdSe core-shell quantum dots. Several peculiar behaviors different from those of type I band alignment have been observed. In the measurement of power dependence of PL, we observe that the peak energy increases with the third root of excitation intensity. The integrated PL intensity varies with excitation intensity as a linear relation. These observation can be interpreted in terms of the band bending effect due to the spatially phoexcited carriers in a type-II band alignment. In addition, we get the exciton binding energy about 17.5 meV, which is much larger than that of quantum wells, but comparable with the theoretical prediction of the exciton energy of quantum dots.

II.Relaxation dynamics of luminescence in CdSe/ZnS core-shell type I quantum dots
We report investigation of PL dynamics of CdSe/ZnS core-shell type-I quantum dots. The PL intensity shows a biexponential decay behavior, which has been observed. We find that the radiactive recombination processes consist of a fast decay (~1 ns) and slow decay component (~10 ns). Due to the photon energy and temperature dependence of decay time experiments, we suggest that the fast and slow decay times involve recombination process of the photoinduced charged exciton and the band edge excitons.

1.Introduction......................................1
2.Theorectical Background...........................5
2.1Photoluminescence................................5
2.2.1 Introduction..................................5
2.2.2 Band structure................................5
2.2.3 Calculation of the effective bandgap of type I QDs.................................................6
2.2.4 Calculation of the exciton binding energy of
type II QDs.........................................7
2.2.5 Several recombination processes...............9
2.2.6 PL Apparatus.................................10
2.2 Time-domain Lifetime...........................15
2.2.1 Introduction.................................15
2.2.2 Meaning of the Lifetime or Decay Time........15
2.2.3 Lifetimes of band edge excitons in CdSe QDs..17
2.2.4 Time Resolved PL Apparatus...................20
3.Optical properties of CdTe/CdSe core-shell type II quantum dots.......................................23
3.1 Introduction...................................23
3.2 Sample preparation.............................25
3.3 Experiment.....................................27
3.4 Results and discussion.........................28
3.5 Summary........................................43
4.Relaxation dynamics of luminescence in CdSe/ZnS core-shell type I quantum dots..........................46
4.1 Introduction...................................46
4.2 Sample preparation.............................48
4.3 Experiment.....................................50
4.4 Results and discussion.........................51
4.5 Summary........................................63
5.Conclusion.......................................66

References(Chapter 1)

1.M. G. Bawendi, M. L. Steigerwald, and L. E. Brus, Annu.
Rev. Phys Chem. 41, 477 (1990).
2.J. R. Heath, Science, 270, 1315 (1995).
3.J. Tittel, W. Gohde, F. Koberling, T. Basche, A.
Kornowski, H. Weller, and A. Eychmuller, J. Phys. Chem.
B 101, 3013 (1997).
4.W. Z. Lee, G. W. Shu, J. C. Wang, J. L. Shen, C. A. Lin,
W. H. Chang, R. C. Ruaan, W. C. Chou, C. H. Lu, and Y.
C. Lee, Nanotechnology 16, 1 (2005).
5.L. Brus, Appl. Phys. Lett. 53, 465 (1991).
6.C. P. Collier, T. Vossmeyer, and J. R. Heath Annu. Rev.
Phys Chem. 49, 371 (1998).
7.M. Bruchez, Jr., M. Moronne, P. Gin, S. Weiss, and A. P.
Alivisatos, Science 281, 2013 (1998).
8.K. Sungjee, F. Brent, E. H. Jürgen, and B. Moungi, J.
Am. Chem. Soc. 125, 11466 (2003).
9.A. R. Kortan, R. Hull, R. L. Opila, M. G. Bawendi, M. L.
Steigerwald, P. J. Carroll, and L. E. Brus, J. Am. Chem.
Soc. 112, 1327 (1990).
10.S. T. Lee, J. Haetty, and A. Petrou, Phys. Rev. B 53,
12912 (1996).
11.M. Larsson, A. Elfving, P. O. Holtz, G. V. Hansson, and
W. X. Ni, Appl. Phys. Lett. 82, 4785 (2003).
12.Y. S. Chiu, M. H. Ya, W. S. Su, and Y. F. Chen, J.
Appl. Phys. 92, 5810 (2002).

References(Chapter 2)

1.L. E. Brus, J. Chem. Phys. 80, 4403 (1984).
2.U. E. H. Laheld, F. B. Pedersen, and P. C. Hemmer, Phys.
Rev. B 48, 4659 (1993).
3.U. E. H. Laheld, F. B. Pedersen, and P. C. Hemmer, Phys.
Rev. B 52, 2697 (1995).
4.J. R. Lakowicz, Principles of Flurescence Spectroscopy
(Academic, New York 1999), p.95.
5.Al. L. Efros, M. Rosen, M. Kuno, M. Nirmal, D.J. Norris,
and M. Bawendi, Phys. Rev. B 54, 4843 (1996).
6.W. Z. Lee, G. W. Shu, J. C. Wang, J. L. Shen, C. A. Lin,
W. H. Chang, R. C. Ruaan, W. C. Chou, C. H. Lu, and Y. C. Lee, Nanotechnology 16, 1 (2005).

References(Chapter 3)

1.S. T. Lee, J. Haetty, and A. Petrou, Phys. Rev. B 53,
2912 (1996).
2.M. Larsson, A. Elfving, P. O. Holtz, G. V. Hansson, and
W. X. Ni, Appl. Phys. Lett. 82, 4785 (2003).
3.Y. S. Chiu, M. H. Ya, W. S. Su, and Y. F. Chen, J. Appl.
Phys. 92, 5810 (2002).
4.F. Hatami, M. Grundmann, N. N. Ledentsov, F.
Heinrichsdorff, R. Heitz, J. Bohrer, and D. Bimberg,
Phys. Rev. B 57, 4635 (1998).
5.S. V. Zaitsev, A. A. Maksimov, V. D. Kulakovskii, and I.
I. Tartakovskii, J. Appl. Phys. 91, 652 (2002).
6.H. Cao, J. Y. Xu, W. H. Xiang, Y. Ma, S. H. Chang, S. T.
Ho, and G. S. Solomon, Appl. Phys. Lett. 76, 3519 (2000).
7.S. W. Lee, K. Hirakawa, and Y. Shimada, Appl. Phys.
Lett. 75, 1428 (1999).
8.E. Leobandung, L. Guo, Y. Wang, and S. Y. Chou, Appl.
Phys. Lett. 67, 938 (1995).
9.D. Bimberg, and N. Ledentsov, J. Phys. Condens. Matter.
15, R1063 (2003).
10.H. Pettersson, L. Btááh, N. Carlsson, W. Seifert, and
L. Samuelson, Appl. Phys. Lett. 79, 78 (2001).
11.a) H. Weller, Adv. Mater. 5, 88, (1993). b) V. L.
Colvin, M. C. Schlamp, and A. P. Alivisatos, Nature
370, 354 (1994). c) W. C.W. Chan, and S. Nie, Science
281, 2016 (1998). d) A. J. Nozik, Phys. E 14, 115
(2002).
12.Z. A. Peng, X. Peng, J. Am. Chem. Soc. 123, 183 (2001).
13.K. Sungjee, F. Brent, E. H. Jürgen, and B. Moungi, J.
Am. Chem. Soc. 125, 11466 (2003).
14.L. E. Brus, J. Chem. Phys. 80, 4403 (1984).
15.J. M. Iannelli, J. Maserjian, B. R. Hancock, P. O.
Andersson, and F. J. Grunthaner, Appl. Phys. Lett. 54,
301 (1989).
16.C. Weisbuch, B. Vinter, Quantum Semiconductor
Structures (Academic, Boston, 1991), p. 20.
17.U. E. H. Laheld, F. B. Pedersen, and P. C. Hemmer,
Phys. Rev. B 48, 4659 (1993).
18.U. E. H. Laheld, F. B. Pedersen, and P. C. Hemmer,
Phys. Rev. B 52, 2697 (1995).
19.Z. Y. Xu, Z. D. Lu, X. P. Yang, Z. Zheng, and J. Z. Xu,
Phys. Rev. B 54, 11528 (1996).
20.R. Seguin, S. Rodt, A. S trittmatter, L. Reimann, T.
Bartel, A. Hoffmann, D. Bimberg, E. Hahn, and D.
Gerthsen, Appl. Phys. Lett. 84, 4023 (2004).

References(Chapter 4)

1.S. T. Lee, J. Haetty, and A. Petrou, Phys. Rev. B 53,
12912 (1996).
2.D. Bimberg, M. Groundmann, and N. N. Ledentsov, Quantum
Dot Heterostructures (New Yourk : Wiley, 1998)
3.M. Schlamp, X. Peng, and A. P. Alivisatos, J. Appl.
Phys. 82, 5837 (1997).
4.B.O. Dabbousi, M. G.. Bawendi, O. Onitsuka, and M. F.
Rubner, Appl. Phys. Lett. 66, 1316 (1995).
5.V. L. Colvin, M. C. Schlamp, and A. P. Alivisatos,
Nature (London) 370, 354 (1994)
6.C. P. Collier, T. Vossmeyer, and J. R. Heath, Annu. Rev.
Phys. Chem. 49, 371 (1998).
7.V. I. Klimov et al., Science 290, 314 (2000).
8.M. Bruchez, Jr. et al., Science 281, 2013 (1998).
9.C. Landes, C. Burda, and M. A. El-Sayed, J. Phys. Chem.
B 105, 2981 (2001).
10.X. Wang, L. Qu, J. Zhang, X. Peng, and M. Xiao Nano
Lett. 3, 1103 (2003).
11.X. Wang, J. Zhang, A. Nazzal, M. Darangh, and M. Xiao
Appl. Phys. Lett. 81, 4829 (2002).
12.A. Javier, D. Magana, T. Jennings, and G. F. Strouse,
Appl. Phys. Lett. 83, 1423 (2003).
13.W. Z. Lee, G. W. Shu, J. C. Wang, J. L. Shen, C. A.
Lin, W. H. Chang, R. C. Ruaan, W. C. Chou, C. H. Lu,
and Y. C. Lee, Nanotechnology 16, 1 (2005).
14.A. R. Kortan, R. Hull, R. L. Opila, M. G. Bawendi, M.
L. Steigerwald, P. J. Carroll, and L. E. Brus, J. Am.
Chem. Soc. 112, 1327 (1990).
15.M. A. Hines, P. J. Guyot-Sionnest, Phys. Chem. 100, 468
(1996).
16.B. O. Dabbousi, J. R. Viejo, F. V. Mikulec, J. R.
Heine, H. Mattoussi, R. Ober, K. F. Jensen, and M. G.
Bawendi, J. Phys. Chem. B, 101, 9463 (1997).
17.J. Bellessa, V. Voliotis, R. Grousson, X. L. Wang, M.
Ogura, and H. Matsuhata, Phys. Rev. B 58, 9933 (1998).
18.V. A. Fonoberov, and A. A. Balandin, Phys. Rev. B 70,
195410-1 (2004).
19.Al. L. Efros, M. Rosen, M. Kuno, M. Nirmal, D.J.
Norris, and M. Bawendi, Phys. Rev. B 54, 4843 (1996).
20.C. Gourdon, and P. Lavallard, Phys. Status Solid B 153,
641 (1989).
21.E. Cohn, and M. D. Sturge, Phys. Rev. B 25, 3828 (1982).
22.M. Strassburg, M. Dworzak, H. Born, R. Heitz, and A.
Hoffmann, Appl. Phys.Lett. 80, 473 (2002).
23.H. Gotoh, H. Ando, T. Takagahara, H. Kamada, A. Chavez-
Pirson, and J. Temmyo, Jpn. J. Appl. Phys. 36, 4204
(1997).