本論文中我們利用有機金屬化學氣相晶法在Si(111)基板上以約30nm的氧化鋁為緩衝層成長氮化鎵薄膜。結晶性由XRD繞射曲線顯示可獲得高品質的六方結構，但是由掃描是電子顯微鏡(SEM)中發現薄膜中有很多的裂痕及缺陷存在，利用光激發螢光頻譜（PL）量測發現在光特性上並沒有很明確的響應。
　　另外本論文並討論以InGaN/Gan量子點製作的光檢測器，此光檢測器將量子點生長在主動區的量子井中，在製作成元件前，在室溫下以光激發螢光頻譜（PL）量測，其最高強度發生在波長464.6nm，辦高寬(FWHM)為24.2 nm。在此量子點光檢測器的量測中發現，最大的光響應產生在波長350nm，並且在波長400nm到440nm之間，光響應幾乎是不變的，並且發現最小的光響應發生在波長465 nm。

　　GaN films were grown on Si(111) substrates by home made MOVPE system using a vertical reactor. The low-temperature AlN buffer layer,30 nm in thickness, was grown on 7000C. The high temperature GaN films were grown at 10600C. XRD observation showed that the films are well oriented hexagonal GaN. But SEM observation showed that there were many cracks and defects in the films. The PL measurement results showed the light response of the films were not clear.
　　We successfully fabricated a novel device: InGaN/GaN multi-quantum dot (MQD) p-n junction photodiodes, and discussed the characteristics of fabricated PDs. We achieved nanoscale InGaN self-assembled QDs in the well layers of the active region. It was found that the maximum responsivity of the fabricated MQD p-n junction PD was observed at 350 nm, and the responsivity was nearly a constant from 400 nm to 440 nm. It was also found that the minimum of spectral response was measured at 465 nm.

Abstract …………………………………………………………………I

Content…………………………………………………………V

Table Captions……………………………………………………VII

Figure Captions……………………………………………………VIII

Chapter 1 Introduction ……………………………………………1
1-1 Suitable substrate for GaN growth…………………………………………1
1-2 Different methods for GaN growth…………………………………………2
1-3 High Quality GaN…………………………………………………………4
1-4 Theory of the Photodetector…………………………………………………6

Chapter 2 MOCVD System and Measurement Equipments…8
2-1 The MOCVD System…………………………………………………8
2-2 The photoluminescence system……………………………………………9
2-3 The XRD……………………………………………………………………9
2-4 Current-Voltage Measurement under Different Irradiation…………………10
2-5 Spectral Response…………………………………………………………11

Chapter 3 Growth of GaN by MOVPE………………………………12
3-1 Experimental Procedure………………………………………………12
3-2 Results and Discussion…………………………………………………14
3-3 Conclusion ………………………………………………………………18

Chapter 4 Fabrication and Measurement of Quantum Dot
Photodetectors……………………………………………20
4-1 Fabrication for p-n junction multiple quantum dot(MQD) photodectectors.20
4-2 I-V characterization……………………………………………………23
4-3 Spectra response…………………………………………………………24
4-4 Conclusion………………………………………………………………25

Chapter 5 Summary…………………………………………………26

References………………………………………………………………………27

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