Study of Si/SiGe Multiple Quantum Well(MQW) Infrared Photodetector 王宗良、黃俊達
E-mail: [email protected]
ABSTRACT
The SiGe based separate-absorption-multiplication avalanche-photodiode（SAMAPD）and has been implemented for the first time. The structure of SAMAPD, in our work, is P +-Si/MQW-(SiGe/Si)/ i-SiGe/N+-Si, in which the i-SiGe and quantum well structure of SiGe/Si are deposited by ultra-high-vacuum chemical-vapor-deposition (UHVCVD) system. In this structure，the thickness of i-Si0.8Ge0.2 layer is about 150nm and quantum structure is of Si (25 nm)/Si0.8Ge0.2( 5 nm) with five periods.
Experiment results shows that the current increases sharply at about 2 V reverse bias, we speculates that the avalanche effect occurred at this voltage. Two structures of dot and net are processed in our studies. We found that the photo-to-dark current ratio of Iphoto/Idark was 15.19 without and 17.9 with covered by Al thin film for dot electrodes at 1 V reverse bias voltage. A higher photo-to-dark current ratio was obtained for net electrodes, the Iphoto/Idark is 52.6 without covered by Al thin film; after covered by Al thin film, the Iphoto/Idark achieved a high value of 134. In addition, the solar cell performance with this structure is measured by using a simulated solar source of 1000W/cm2 and a high conversion efficiency of 8.26% is obtained for dot electrodes with Al thin films.
Keywords : MQW ; SiGe ; photodetector ; evaporation ; solar cells
Table of Contents
封面內頁 簽名頁 授權書．．．．．．．．．．．．．．．．．．．．．．．．．iii 中文摘要．．．．．．．．．．．．
．．．．．．．．．．．．iv 英文摘要．．．．．．．．．．．．．．．．．．．．．．．．v 誌謝 ．．．．．．．．．
．．．．．．．．．．．．．． ．．vi 目錄．．．．．．．．．．．．．．．．．．．．．．．．．．vii 圖目錄．．．
．．．．．．．．．．．．．．．．．．．．．．ix 表目錄．．．．．．．．．．．．．．．．．．．．．．．．．xi 第 一章 前言 ．．．．．．．．．．．．．．．．．．．．．．01 第二章 原理 ．．．．．．．．．．．．．．．．．．．．
．．03 2.1 矽鍺的基本特性．．．．．．．．．．．．．．．．．．．03 2.2光檢測器原理．．．．．．．．．．．．．．
．．．．．．．07 2.2.1 光的種類．．．．．．．．．．．．．．．． ．．．． 07 2.2.2 輻射轉換．．．．．．．．．．
．．．．．．．．．．．07 2.2.3 光的吸收．．．．．．．．．．．．．．．．．．．．．08 2.2.4 P-N接面．．．．．．
．．．．．．．．．．．．．．． 09 2.2.5 P-N與PIN感光二極體．．．．．．．．．．．．．．．．12 第三章 元件製程
、光電量測與材料分析 ．．．．．．．．．．．17 3.1薄膜成長系統．．．．．．．．．．．．．．．．．．．．．17 3.2 樣品清洗．．．．．．．．．．．．．．．．．．．．．．．18 3.3蒸鍍機系統(Thermal Evaporator System)．．．．．．
．19 3.4傳統爐管退火系統(Conventional Furnace Annealing)．19 3.5光電量測系統．．．．．．．．．．．．．．．．．．
．．．20 3.5.1電性量測(Current ─ Voltage measurement)．．．．20 3.5.2光譜響應量測(Spectral response measurement) ．
．21 3.5.3響應率量測(Responsivity measurement)．．．． ．．21 第四章 實驗結果與討論．．．．．．．．．．．．．．．
．．． 25 4.1歐姆電極．．．．．．．．．．．．．．．．．．．．．．．25 4.2 PL量測 ．．．．．．．．．．．．．．
．．．．．．．．．28 4.3電性量測．．．．．．．．．．．．．．．．．．．．．．．29 4.4光譜響應．．．．．．．．
．．．．．．．．．．．．．．．39 4.5太陽能電池之量測．．．．．．．．．．．．．．．．．．．41 第五章 結論與未 來展望．．．．．．．．．．．．．．．．．．44
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