臺灣博碩士論文加值系統

我們選擇利用由下而上的熱蒸鍍方法合成出矽鍺量子點，並第一次結合由上而下的分子束磊晶技術，成功的製作出矽鍺合金量子點紅外線偵測器。我們使用了拉曼光譜及穿透式電子顯微鏡後，對這些量子點的結構和光學特性做了有詳細的研究。已可找出量子點的大小分佈和晶格常數。我們發現矽鍺量子點有一大約 0.5 Torr 之臨界成長壓力，並清楚地觀察到這些矽鍺合金量子點具有球形的外觀並且確實是矽鍺合金的結構。另外，我們可以藉由改變其組成元素之蒸鍍速率而控制其成分，並利用超音速震洗，用甲醇處理群聚的矽鍺量子點以形成單層的矽鍺量子點。然後,利用分子束磊晶在這些矽鍺量子點上面生長了矽晶層，完成了紅外線偵測器。由實驗結果顯示在零偏壓的情況下，波長為 2 微米的響應度峰值具有 4.2 毫安培/瓦，並且達到5.0 x 1010 公分-赫玆1/2/瓦 之高偵測度為。說明了此元件具有操作在高溫 240 K 的能力。

The thermal evaporation method was chosen to synthesize spherical SiGe nanoparticles, which is basically a bottom-up approach. By combining the subsequent top-down approach, i.e., molecular beam epitaxy, the SiGe alloy quantum dot infrared photodetectors (QDIP) have been successfully fabricated for the first time. By using the Raman spectra and transmission electron microscopy (TEM) image, the structural and optical properties of these dots were studied in detail. The size and distribution and the lattice constant for these dots can be found. A critical growth pressure about 0.5 torr for the SiGe nanoparticles is found. Clearly, the SiGe quantum dots are spherical in shape and indeed an alloy of Si and Ge. The composition of these dots could be adjusted by varying the evaporation rate of constituent elements. The clusters of SiGe dots are treated with methanol in the ultrasonic bath to form a single layer of SiGe dots. Then, the Si layers were grown on top of the SiGe dots by molecular beam epitaxy (MBE). Infrared photodetectors were fabricated. The results show the peak responsivity at 2μm to be 4.2 mA/W and high specific detectivity (D*) achieved is 5.0 x 1010 cm-Hz1/2/W under zero bias. This device is capable of operation up to 240 K with good performance.

Contents
Chapter 1 Introduction 1
Chapter 2 Growth Mechanism of Nanoparticles and Experimental Procedure 6
2.1 Nanoparticles Produced by Thermal Evaporation Method 6
2.2 System Setup and Growth Procedures 12
2.3 Transmission Electron Microscopy 12
2.4 Raman Spectra 14
2.5 Measurement System of the Infrared Photodetector 15
2.5.1 Current-Voltage Measurement 15
2.5.2 Spectral Response Measurement 15
Chapter 3 The Characteristics of Silicon Germanium Alloy Nanoparticles……..19
3.1 Growth Conditions 19
3.2 The Effect of Substrate Temperature 23
3.3 The Effect of Chamber Gas Pressure 31
3.3.1 Low-Pressure Range 31
3.3.2 High-Pressure Range 38
3.4 The Effect of Applied Current 47
Chapter 4 Quantum Dot Infrared Detector………55
4.1 Thermal Radiation 55
4.2 Infrared Detectors 56
4.2.1 Mechanisms of Infrared Detectors 56
4.2.2 Responsivity 59
4.2.3 Noise Equivalent Power (NEP) and Detectivity 63
4.3 Quantum Dot Infrared Photodetectors 64
4.3.1 Single Layer of SiGe Dots 65 4.3.2 Samples Prepared 69
4.3.3 Transmission Electron Microscopy Images 73
4.4 Device Fabrication Processes 76
Chapter 5 The Electrical and Optical Properties of Quantum Dot Infrared Photodetector 84
5.1 Quantum Dot Infrared Photodetector with Asymmetric Structure 84
5.1.1 Sample Structure 84
5.1.2 Results and Discussions 86
5.2 Quantum Dot Infrared Photodetector with Symmetric Structure 90
5.2.1 Sample Structure 90
5.2.2 Results and Discussion of QDIP R70 90
5.2.3 Results and Discussion of QDIP R71 105
5.3 Comparisons of R52, R70 and R71 Characteristic 110
Chapter 6 Conclusions 117
Bibliography 120

Bibliography
[1] A. I. Ekimov, A. L. Efros and A. A. Onushchenko, Solid State Commun., 56, 921, 1985.
[2] E. Hanamura, Phys. Rev. B, 37, 1273, 1988.
[3] Y. Kayanuma, Phys. Rev. B, 38, 9797, 1988.
[4] A. Henglein., Chem. Rev., 89, 1861, 1989.
[5] L. Brus, Appl. Phys. A, 53, 465, 1991.
[6] A. P. Alivisatos, Science, 271, 933, 1996.
[7] A. K. Boal, et al, Nature, 404, 746, 2000.
[8] H. Gau, S. Herminghaus, P. Lenz, and R. Lipowsky, Science, 283, 46, 1999.
[9] Z. X. Tang, C. M. Sorenson, K.J. Klabunde and G. C. Hadjipanayis, J. Colloid Interface Sci., 146, 38, 1991.
[10] D. W. Hoffman, R. Roy and S. Komarneni, J. A. Ceram. Soc., 67, 468, 1984.
[11] Y. Kawamura, M. Takagi and M. Akai, Mater. Sci. Eng., 98, 449, 1988.
[12] C. G. Granqvist and R. A. Buhrman, J. Appl. Phys., 47(5), 2200, 1976.
[13] C. W. Lin, S. Y. Lin, S. C. Lee and C. T. Chia, J. Appl. Phys. 91, 1525 (2002)
[14] Y. He, H. Liu, N. Yu and X. M. Yu, NanoStruct. Mater., 7(7), 769, 1996.
[15] Y. He, C. Yin, G. Cheng, L. Wang and X. Liu, J. Appl. Phys., 75(2), 797, 1994.
[16] N. L. Mandich, V. E. Bondybey, W. D. Reents, J. Chem. Phys., 86, 4245, 1987.
[17] H. Hahn and R. S. Averback, J. Appl. Phys., 67(2), 1113, 1990.
[18] G. M. Chow, C. L. Chien and A. S. Edelstein, J. Mater. Sci., 6, 8, 1991.
[19] H. J. Fecht, NanoStruct. Mater., 6, 33, 1995.
[20] J. W. Kim, J. E. Oh, S. C. Hong, C. H. Park, and T. K. Yoo, IEEE electron Device Lett. 21, 329 (2000)
[21] S. Yatsuya, S. Kasukabe and R. Uyeda, Jpn. J. Appl. Phys., 12(11), 1973
[22] C. G. Granqvist and R. A. Buhrman, J. Appl. Phys., 47, 2200, 1976.
[23] N. Ichinose, Y. Ozaki and S. Kashu, Superfine Particle Technology, 1992.
[24] S. G. Kim and J. R. Brock, J. Appl. Phys., 60, 509, 1986.
[25] V. Haas, H. Gleiter and R. Birringer, Scr. Metall. Mater., 28, 721, 1993.
[26] S. Veprek, Z. Iqbal and F. A. Sarrot, Philosophical Magazine B, 45(1), 137, 1982.
[27] P. Becker, P. Seyfried, H. Siegert and Z. Physik, B48, 17, 1982.
[28] Z. Sui, H. H. Burke and I. P. Herman, Phys. Rev. B, 48(4), 1993.
[29] M. I. Alonso and K. Winer, Physical Review B, 39(14), 10056, 1989.
[30] R. Tsu, Proc. SPIE, 276, 78, 1981.
[31] M. I. Alonso and K. Winer, Physical Review B, 39(14), 10056, 1989.
[32] S. Veprek, Z. Iqbal, H. R. Oswald, F. A. Sarrot, J. J. Wagner and P. Webb, Solid St. Commun., 39, 530, 1981.
[33] S. Veprek, Z. Iqbal and F. A. Sarrot, Philosophical Magazine B, 45(1), 137, 1982.
[34] J. W. Gibbs, Collected Works, edited by W. R. Longley and R. G. van Name (Longmans, Green and Co., NEW YORK, 1931).
[35] T. Hayashi, T. Ohno, S. Yatsuya and R. Uyeda, J. J. Appl. Phys., 16, 705, 1977.
[36] Yano, Fumiko, J. J. Appl. Phys., Part 2: Letters 36, 6A, 1997.
[37] The Physics of Quantum Well Infrared Photodetectors, edited by K. K. Choi (US Army Research Laboratory, Mary land 1997)
[38] J. Y. L. Ho and K. S. Wong, IEEE Photon. Tech. Lett., 8, 1064
[39] T. L. Lin and J. Maserjian, Appl. Phys. Lett., 57, 1422.
[40] P. Kruck, M. Helm, T. Fromherz, G. Bauer, J. F. Nützel and G. Abstreiter, Appl. Phys. Lett., 69, 3372.
[41] A. I. Yakimov, A. V. Dvurechenskii, A. I. Nikiforov, and Yu. Yu. Proskuryakov, J. J. Appl. Phys., 89, 5676.
[42] O. A. Shegai, K. S. Zhuravlev, V. A. Markov, A. I. Nikiforov and O. P. Pchelyakov, Semiconductors, 34, 1311.
[43] Semiconductor Quantum Wells and Suprtlattices for Long-Wavelength Infrared Dtetctors, edited by M. O. Manasreh, 1993.
[44] Quantum Dot Heterostructures., edited by D. Bimberg, M. Grundmann, N. N. Ledentsov, 1999.
[45] Theory of Dislocations, edited by J. P. Hirth and J. Lothe.
[46] M. Albrecht, H. P. Strunk, R. Hull and J. M. Bonar, Appl. Phys. Lett., 62, 2206,1993.
[47] Investigation of Superlattice Infrared Photodetector to reach the Background Limited Performance at High Temperature, edited by J. M. Chen, Nation Taiwan University, 2000.
[48] Modern GaAs Processing Methods, edited by Ralph Williams, 1990.
[49] D. Pan and E. Towe., Appl. Phys. Lett. 75, 2719, 1999.
[50] B. F.Levine, K. K. Choi, C. G.Bethea, J. Walker, and R. J. Malik, Appl. Phys. Lett., 51, 934, 1987.
[51] S. Kim, H. Mohseni, M. Erdtmann, M. Michel, C. Jelen, and M. Razeghi. Appl. Phys. Lett., 73, 963, 1998.
[52] K. K. Choi, B. F. Levine, C. G. Bethea, J. Walker, and R. J. Malik, Appl. Phys. Lett., 52, 1979, 1988.
[53] B. F. Levine, J. Appl. Phys., 74, R1, 1993.
[54] M. Yang, J. C. Sturm and J. Prevost, Phys. Rev. B, 56, 1973, 1997.