Epitaxy of Si-Ge-Sn-based heterostructures for CMOS-integratable light emitters. (May 2019) - von den Driesch, Nils
Highlights: We demonstrate epitaxy of GeSn and SiGeSn alloys for optical applications. Both semiconductors are combined to form direct bandgap group IV heterostructures. Multi quantum wells show highest PL efficiency and lowest lasing thresholds. Wavelength-tunable electroluminescence is demonstrated at room temperature. Abstract: The recent rise of GeSn-based optically pumped lasers have multiplied the efforts to fabricate a fully CMOS compatible and group IV-based light emitter. Their integration with Si-based electronics may yield heavily reduced power consumption in integrated circuits and pave the way towards new sensing or medical applications. Here, we discuss the epitaxy of group IV GeSn and SiGeSn semiconductors and show their suitability for light emitting applications. Double and multi quantum well heterostructures are evaluated, whereby the latter enables an inherently easier control over the formation of deleterious misfit defects. Consequently, microdisk lasers fabricated from those show greatly enhanced light emission and reduced lasing thresholds. The use of in-situ p-i-n doping schemes allow the formation of light emitting diodes, resulting in electrically-enabled light emission already at room temperature.