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標題: | 銻磷砷化銦/砷化鎵光學與電氣傳導特性研究 Optical and electrical properties of InAsPSb bulk epilayers grown on GaAs substrates |
作者: | Yu-Chieh Chou 周鈺傑 |
指導教授: | 林浩雄 |
關鍵字: | MBE,InAsPSb,Mott transition,configuration coordination model, 銻磷砷化銦,Mott轉變,結構協調模型, |
出版年 : | 2009 |
學位: | 碩士 |
摘要: | 本篇論文中,我們研究以氣態分子束磊晶成長一系列不同成份銻磷砷化銦塊材之光激發特性。在As成份<0.65之四元樣品中,樣品之PL放光譜型為高斯曲線分佈,我們可以利用結構協調模型(configuration coordination model)解釋深階能階放光;而在As成份為0.65樣品,InAs0.647P0.264Sb0.089,其低溫PL為帶尾能階復合放光;當溫度升至高溫時,PL為導電帶至價電帶的放光。
此外,我們還研究銻磷砷化銦四元合金和砷化銦化合物半導體材料的電性。我們以分子束磊晶技術成長無摻雜、鈹摻雜的銻磷砷化銦(Be-doped InAsPSb)、以及鈹摻雜的砷化銦(Be-doped InAs)。然後以20~300 K變溫霍爾效應量測(Hall effect)來分析這些樣品的電氣傳導特性。我們以Mott criterion以及two-band conduction,解釋載子濃度在高溫時隨溫度而下降的特性以及在<100 K時的無冷凝現象(non- freeze-out behavior)。此外我們也探討在這些樣品中遷移率(mobility)與散射機制(scattering)之間的關係。我們利用一個退化半導體解離雜質散射模型來說明低溫時不隨溫度改變的遷移率。而在高溫時,我們發現合金散射與晶格聲子散射分別主宰了InAsPSb和InAs的遷移率。 We report a systematic investigation on the photoluminescence (PL) of quaternary InAsPSb grown on GaAs substrates by gas-source molecular beam epitaxy (GSMBE). When the As composition < 0.65, samples show a Gaussian-like PL band, which can be illustrated by a configuration coordination model. The sample with the highest As composition, InAs0.647P0.264Sb0.089, however, shows a PL transition dominated by band tail state recombination at low temperature. As the temperature increases, band-to-band recombination is identified from its PL spectra. We also have studied the electrical properties of undoped and Be-doped InAsPSb and Be-doped InAs in the temperature range 20-300 K using Hall effect measurement. The carrier concentration slightly decreases with temperature in high temperature region and does not freeze out as the temperature is below 100 K. Mott transition and two-band conduction are attributed to the observed behaviors. The low temperature mobility in all samples is nearly temperature-invariant, which is ascribed to an ionized impurity scattering mechanism for degenerate semiconductors. Alloy scattering and lattice scattering are the dominant scattering mechanism of InAsPSb and InAs at high temperatures, respectively. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/43711 |
全文授權: | 有償授權 |
顯示於系所單位: | 電子工程學研究所 |
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