在本論文中我們研究了三種透明材料的特性。這些材料分別為氮化鈦、電子束蒸著氧化銦錫、濺鍍氧化銦錫。我們研究這些材料的基本特性包括:導電度、透明度、有效位障高度。氮化鈦、電子束蒸著氧化銦錫、濺鍍氧化銦錫的塊材電阻值分別為34.9 KΩ、237 Ω、171 Ω。濺鍍氧化銦錫、氮化鈦、電子束蒸著氧化銦錫厚度為1000 Å，在400 nm的波長下的透明度分別是94%、62%、85%。濺鍍氧化銦錫、氮化鈦、電子束蒸著氧化銦錫的蕭基位障高度分別為0.462 eV、0.585 eV、0.945 eV。
我們將這些透明材料用在氮化鎵金半金光檢測器上當作透明電極。在5V的偏壓下，濺鍍氧化銦錫、氮化鈦、電子束蒸著氧化銦錫金半金光檢測器的光暗電流比值分別為100.36、103、104.25。在三種材料當中，我們可以發現電子束蒸著氧化銦錫是最適合用來作氮化鎵金半金光檢測器的電極。在一個給定的頻寬500Hz下，我們可以算出氮化鎵金半金光檢測器相關的雜訊功率密度、歸一化的檢測度為1.51×10-10 W 、 2.96×109 cmHz0.5W-1。
進一步而言，我們想要降低濺鍍氧化銦錫、氮化鈦金半金光檢測器的暗電流。因此我們在電極與氮化鎵之間插入了一層絕緣層。我們在氮化鈦和氮化鎵之間加入了鈦酸鍶鋇，在濺鍍氧化銦錫和氮化鎵之間加入了光激化學氣相沉積的二氧化矽。在加入3 nm的鈦酸鍶鋇時，我們可以達成氮化鈦／鈦酸鍶鋇／氮化鎵的金屬-絕緣層-半導體光檢測器的最大光暗電流比值為2.5×104。利用光激化學氣相沉積的二氧化矽來當作絕緣層，氮化鎵金屬-絕緣層-半導體光檢測器在暗電流方面會有7個數量級的改善。在4V的偏壓下，氧化銦錫／10 nm二氧化矽／氮化鎵的金屬-絕緣層-半導體光檢測器光暗電流比值約為1.51×103。
我們也研究了氮化銦鎵／氮化鎵的多層量子井p-n接面光檢測器。在0.4V的逆向偏壓下，可以發現光暗電流的比值超過10５。在0.1V、1V、3V的逆向偏壓下，氮化銦鎵／氮化鎵的多層量子井p-n接面光檢測器的最大響應度分別是1.28 A/W、1.37 A/W、1.76 A/W。在一個給定的頻寬500Hz下，我們可以發現氮化銦鎵／氮化鎵的多層量子井p-n接面光檢測器相關的雜訊功率密度、歸一化的檢測度為6.34×10-13 W、4.45×1011 cmHz0.5W-1。

In this thesis, we study the characteristics of three transparent materials. These transparent materials are TiN, E-beam ITO and Sputtering-ITO, respectively. We study the basic characteristics including conductivity, transmittance and effective barrier height of these materials. The bulk resistance of TiN, E-beam ITO and Sputtering-ITO films was 34.9 KΩ,237 Ω and 171 Ω, respectively. The transmittance of Sputtering-ITO, TiN and E-beam ITO films for thickness of 1000Å was 94%, 62% and 85% at wavelength of 400 nm, respectively. The Schottky barrier height of Sputtering-ITO, TiN and E-beam ITO on GaN were 0.462eV, 0.585eV and 0.945eV, respectively.
We used these transparent materials on GaN MSM photodetectors as transparent electrodes. The photo/dark contrast of Sputtering-ITO, TiN and E-beam ITO MSM photodetectors were 100.36, 103 and 104.25 at 5V bias, respectively. It could be found that E-beam ITO was the most suitable electrode for GaN MSM photodetectors among three materials. For a given bandwidth of 500 Hz, the corresponding noise equivalent power (NEP) and normalized detectivity D* for GaN MSM photodetector are calculated to be 1.51×10-10 W and 2.96×109 cmHz0.5W-1.
Furthermore, we would like to reduce the dark currents of Sputtering-ITO and TiN MSM photodetectors. Therefore we inserted an insulating layer between electrode and GaN. We inserted BST layer between TiN and GaN, photo-SiO2 layer between Sputtering-ITO and GaN. With a 3 nm-thick BST interlayer, it was found that we could achieve a maximum 2.5×104 photocurrent to dark current contrast in TiN/BST/GaN MIS photodetectors. The GaN MIS photodetectors has a 7 orders improvement in dark current by using the photo-SiO2 films as the insulating layer. The photo/dark contrast was about 1.51×103 at 4V bias for ITO/10nm photo-SiO2/GaN MIS photodetectors.
We investigated the characteristics of InGaN/GaN MQW p-n junction photodiodes. With a 0.4 V applied reverse bias, it was found that photocurrent to dark current contrast ratio was higher than 105. The peak responsivity of InGaN/GaN MQW p-n junction photodiodes equals to 1.28 A/W, 1.37 A/W and 1.76 A/W when the sample was reversed biased at 0.1 V, 1 V and 3 V, respectively. For a given bandwidth of 500 Hz, the corresponding NEP and normalized detectivity D* of InGaN/GaN MQW p-n junction photodiodes were found to be 6.34×10-13 W and 4.45×1011 cmHz0.5W-1, respectively.

Chapter 1 Reference
[1] S. Strite, M.E. Lin and H. Morkoc, Thin Solid Films, Vol. 231, 197 (1993).
[2] R.F. Davis, Proc. IEEE 5, 702 (1991).
[3] M.A. Khan, M.S. Shur, J.N. Kuzunia, Q. Chen, J. Burm and W. Schaff, Appl. Phys. Lett, Vol. 66, 1083 (1995).
[4] O. Aktas, Z.F. Fan, S.N. Mmohammand, A.E. Botchkarev and H. Morkoc, Appl. Phys. Lett, Vol. 69, 3872 (1996).
[5] H.P. Maruska and J.J. Tietjen, Appl. Phys. Lett, Vol. 15, 327 (1969).
[6] P.B. Perry and R.F. Rutz, Appl. Phys. Lett, Vol. 33, 319 (1978).
[7] S. Itho, N. Nakayama, S. Matsumoto, M. Nagai, K. Nakano, M. Ozawa, H. Okuyama, S. Tomiya, T. Ohata, M. Ikeda, A. Ishibashi and Y. Mori, Jpn. J. Appl. Phys, Vol. 33, 938 (1994).
[8] M.A. Khan, J.N. Kuznia, A.R. Bhattarai and K.T. Ilson, Appl. Phys. Lett, Vol. 62, 1786 (1993).
[9] E.D. Jungbluth, Laser Focus, Vol. 5, 33 (1993).
[10] S. Nakamura, M. Senoh, S. Nagahama and Y. Sugimoto, Jpn. J. Appl. Phys, Vol. 35, 74 (1996).
[11] A. Bykhovski, B. Gelmont and M. Shur, J. Appl. Phys, Vol. 74, 6734 (1993).
[12] P. Kozodoy, M. Hansen, S.P. DenBaars and U.K. Mishra, Appl. Phys. Lett, Vol. 74, 3681(1999).
[13] M.A. Khan, Q. Chen, M.S. Shur, B.T. Dermott, J.A. Higgins, J. Burm, W. Schaff and L.F. Eastman, Electron. Lett, Vol. 32, 357 (1996).
[14] H. Morkoe, S. Strite, G.B. Gao, M.E. Lin, B. Sverdlov and M. Burns, J. Appl. Phys, Vol. 76, 1363 (1994).

Chapter 2 Reference
[1] J.L. Vossen and W. Kern, “Thin Flim Processes”, Academic Press, New York, 131 (1978).
[2] C.Y. Chang and S.M. Sze, “ULSI Technology”, McGraw-Hill, New York, 380 (1996).
[3] J.L. Vossen and W. Kern, “Thin Film Processes”, Academic Press, New York, 24 (1978).
[4] S.I. Shah, “Handbook of Thin Film Process Technology”, Institute of Physics Pub, Bristol, UK, P.A3.0:1 (1995).
[5] S.I. Shah, “Handbook of Thin Film Process Technology”, Institute of Physics Pub, Bristol, UK, P.A3.2:1. (1995).
[6] S.M. Sze, “VLSI Technology”, McGraw-Hill, New York, 387 (1978).
[7] Y. Tarui, J. Hidaka and K. Aota, Jpn. J. Appl. Phys, Vol. 23, 827 (1984).
[8] M. Okuyama, Y. Toyoda and Y. Hamakawa, Jpn. J. Appl. Phys, Vol. 23, 97 (1984).
[9] O. Itoh, Y. Toyoshima, H. Onuki, N. Washida and T. Ibuk, J. Chem. Phys, Vol. 85, 4876 (1986).
[10] H. Okabe, “Photochemistry of small molecules”, Wiely, New York, (1978).
[11] A.M. Goodman, J. Appl. Phys, Vol. 34, 329 (1963).
[12] R.H. Fowler, Phys. Rev, Vol. 38, 45 (1931).

Chapter 4 Reference
[1] M. Razeghi and A. Rogalski, J. Appl. Phys, Vol. 79, 7433 (1996).
[2] E. Monroy, E. Muñoz, F.J. Sánchez, F. Calle, E. Calleja, B. Beaumout, P. Gibart, J.A. Muñoz and F. Cussó, Semicond. Sci. Technol, Vol. 13, 1042 (1998).
[3] G. Parish, S. Keller, P. Kozodoy, J.A. Ibbetson, H. Marchand, P.T. Fini, S.B. Fleischer, S.P. DenBaars and U.K. Mishra, Appl. Phys. Lett, Vol. 75, 2479 (1999).
[4] E. Monroy, M. Hamilton, D. Walker, P. Kung, F.J. Sánchez and M.Razeghi, Appl. Phys. Lett, Vol. 74, 1171 (1999).
[5] A. Osinsky, S. Gangopadhyay, R. Gaska, B. Williams, M.A. Khan, D. Kuksenkov and H. Temkin, Appl. Phys. Lett, Vol. 71, 2334 (1997).
[6] Q. Chen, J.W. Yang, A. Osinsky, S. Gangopadhyay, B. Lim, M.Z. Anwar, M.A. Khan, D. Kuksenkov and H. Temkin, Appl. Phys. Lett, Vol. 70, 2277 (1997).
[7] Z.C. Huang, J.C. Chen and D. Wickenden, J. Cryst. Growth, Vol. 170, 362 (1997).
[8] Y.K. Su, Y.Z. Chiou, F.S. Juang, S.J. Chang and J.K. Sheu, Jpn. J. Appl. Phys, Vol. 40, 2996 (2001).
[9] C.H. Chen, S.J. Chang, Y.K. Su, G.C. Chi, J.Y. Chi, C.A. Chang, J.K. Sheu and J.F. Chen, IEEE Photon. Technol. Lett, Vol. 13, 848 (2001).
[10] J.C. Carrano, D.J.H. Lambert, C.J. Eiting, C.J. Collins, T. Li, S. Wang, B. Yang, A.L. Beck, R.D. Dupuis and J.C. Campbell, Appl. Phys. Lett, Vol. 76, 924 (2000).
[11] H.C. Casey, Jr., G.G. Fountain and R.G. Alley, B.P. Keller and Steven P. DenBaars, Appl. Phys. Lett, Vol. 68, 1850 (1996).
[12] C.T. Lin, Y.K. Su, S.J. Chang, H.T. Huang, S.M. Chang and T.P. Sun, IEEE Photo. Technol. Lett, Vol. 9, 232 (1997).
[13] C.T. Lin, Y.K. Su, H.T. Huang, S.J. Chang, G.S. Chen, T.P. Sun and J.J. Luo, IEEE Photo. Technol. Lett, Vol. 8, 676 (1996).
[14] S.M. Sze, “Physics of Semiconductor Devices, 2nd. Ed.”, Wiley, New York, 225 (1981).
[15] F.A. Padovani and R. Stratton, Solid-State Electron, Vol. 9, 695 (1966).
[16] C.R. Crowell and V.L. Rideout, Solid-State Electron, Vol. 12, 89 (1969).
[17] V.L. Rideout, Solid-State Electron, Vol. 18, 541 (1975).
[18] A.S. Baker and M.I. Ilegems, Appl. Phys. Rev B, Vol. 7, 743 (1993).
[19] P. Hacke, T. Detchprohm, K. Hiramatsu and N. Sawaki, Appl. Phys. Lett, Vol. 63, 2676 (1993).
[20] Y. Park, V. Choong, Y. Gao, B.R. Hsieh and C.W. Tang, Appl. Phys. Lett, Vol. 68, 2699 (1996).
[21] D.W. Kim, Y.J. Sung, J.W. Park and G.Y. Yeom, Thin Soild Films, Vol. 398-399, 87 (2001).
[22] T. Li, D.J.H. Lambert, M.M. Wong, C.J. Collins, B. Yang, A.L. Beck, U. Chowdhury, R.D. Dupuis and J.C. Campbell, IEEE J. Quantum Electron, Vol. 37, 538 (2001).
[23] S.R. Morrison, J. Appl. Phys, Vol. 72, 4104 (1992).
[24] O. Katz, V. Garber and B. Meyler, Appl. Phys. Lett, Vol. 80, 347 (2002).