- 學位論文
矽鍺虛擬基材上成長硒化鋅系異質結構的特性研究
Characterization of ZnSe-based heterostructures grown on GexSi1-x/Si virtual substrates
摘要
在傾斜角度為0度、4度及6度的矽鍺虛擬基材上成長硒化鋅單一磊晶層。使用原子遷移強化磊晶法及熱退火低溫緩衝層，能夠有效的降低硒化鋅單一磊晶層的深能階放射。高結晶品質的硒化鋅單一磊晶層也可由X光繞射分析與穿透式電子顯微鏡的量測結果來印證。成長高品質硒化鋅的技術也被運用於在矽鍺虛擬基材上成長硒化鎘鋅單一磊晶層及硒化鎘鋅/硒化鋅的多重量子井。在此將研究討論在矽鍺虛擬基材上成長硒化鎘鋅/硒化鋅多重量子井的光學特性。而硒化鎘鋅多重量子井的量子侷限效應也可由光激螢光光譜來確認。由隨溫度變化的激子放射能量峰值與線寬，顯示在井寬為1奈米的量子井中其局部性的能態是最少的。在高溫時，熱抑制硒化鎘鋅量子井的激子放射強度，是由於激子受熱活化而從量子井的侷限態進入能障態所致。
並列摘要
ZnSe epilayers were grown on the GexSi1-x /Si virtual substrates with 0o, 4o and 6o off-cut from (100) tilts toward the in-plane [110] direction. Migration enhanced epitaxy and an insert of in-situ thermal annealing low-temperature ZnSe buffer layer effectively decrease the deep-level emission from ZnSe epilayers. The X-ray diffraction analysis and transmission electron microscopy results also show good crystallinity of ZnSe epilayer. The procedures for the growths of high-quality ZnSe were adopted to deposit ZnCdSe epilayers and ZnCdSe/ZnSe multiple quantum wells on the GexSi1-x /Si virtual substrates. Optical properties of ZnCdSe multiple quantum wells grown on GexSi1-x/Si virtual substrate were investigated. Quantum-confinement effect of ZnCdSe multiple quantum wells was identified in the photoluminescence spectroscopy. The evolution of exciton emission peak energy and linewidth as a function of temperature suggests fewer localized states in sample with well-widths of 1 nm. At high temperature, thermal quenching of excitonic emission intensity for ZnCdSe quantum well structures were governed by thermal activation of carriers from quantum well confined states into barrier states.