Resonant cavity enhanced photoluminescence of tensile strained Ge/SiGe quantum wells on silicon-on-insulator substrate

The tensile strained Ge/SiGe multiple quantum wells （MQWs） grown on a silicon-on-insulator （SOI） substrate were fabricated successfully by ultra-high chemical vapor deposition. Room temperature direct band photoluminescence from Ge quantum wells on SOI substrate is strongly modulated by Fabry-Perot cavity formed between the surface of Ge and the interface of buried SiO2. The photoluminescence peak intensity at 1.58 μm is enhanced by about 21 times compared with that from the Ge/SiGe quantum wells on Si substrate, and the full width at half maximum （FWHM） is significantly reduced. It is suggested that tensile strained Ge/SiGe multiple quantum wells are one of the promising materials for Si-based microcavity lijzht emitting devices.     

Si基Ge/SiGeⅠ型量子阱结构的理论设计和实验研究

基于能带工程理论,设计了Si基Ge/SiGeⅠ型量子阱结构。采用超高真空化学气相淀积系统,制备出高质量的Si基Ge/SiGe多量子阱系列材料。当样品中Ge量子阱宽从15nm减少到12nm和11nm时,室温下荧光(PL)光谱观测到量子限制效应引起的直接带跃迁发光峰位的蓝移,峰位的实验值与理论值符合得很好;当Ge量子阱宽逐渐减小到9nm和7nm时,测试得到样品的PL谱峰位却与理论预期出现了较大的差值。进一步的实验表明,这主要是由于量子阱厚度小到一定程度时,量子阱的直接带发光受到抑制,其发光主要源于Ge虚拟衬底。