由發光頻譜判定矽鍺/矽異質接面的能帶結構種類

Abstract

矽/鍺光電元件具有可直接與矽積體電路整合的優點，因此製程上的成本將可獲得降低。此外由於量子結構之異質接面結構的長晶技術進步，近來矽鍺異質接面的光電元件特性已被廣為研究。 在本研究中,使用超高真空化學氣相沉積，成長十週期的矽/矽鍺超晶格結構，並在P型高掺雜區域分別成長了矽塊材以及Si0.9Ge0.1的塊材，此兩種樣品分別稱為Si0.9Ge0.1 capping(矽鍺覆蓋層)樣品以及Si capping(矽覆蓋層)樣品。藉由以發光頻譜(EL)和發光強度與電流特性曲線(LI curve)的量測為出發點，對發光二極體的光學特性展開一系列的計算與討論。其中討論的主要目標鎖定在矽緩衝層的發光特性探討，由此為基礎而嘗試對於Si0.9Ge0.1的覆蓋層與矽緩衝層之間的導電帶結構究竟是type Ⅰ還是typeⅡ提出討論及推測，並從建立一個穩定、可靠的討論、研究架構。

The advantage of the optical electronic component made up by silicon and germanium materials is that it could be fully compatible with the Si-based microelectronic chips. Therefore, the cost of the fabrication could decrease. In addition, the growth techniques for quantum heterojunction structures are in advanced and then the heterojunction structure of silicon or germanium has been studied far and wide recently. In this study, the light-emitting diodes (LEDs) with multi-periods of Si/SiGe superlattice structures are used. The ten periods Si/SiGe superlattice structure are grown by UHV/CVD system and two materials of Si and Si0.9Ge0.1bulk materials which works as capping layer are grown in the P+ doped region. The two samples are called the Si0.9Ge0.1 capping and the Si capping respectively. The study starts by the measurements of the EL spectra and the LI curves. Then, the optical characteristics of the light emitting diode is got and discussed. This discussion is focused on the Si light emission from the buffer layer. Then, by the discussion, the band structure at the boundary between the Si buffer layer and the Si0.9Ge0.1 capping layer is discussed. Finally, a stable and reliable studying framework would be established.