Controllable synthesis of Si-based GeSn quantum dots with room-temperature photoluminescence

GeSn quantum dots (QDs) are regarded as a promising material to improve the performance of GeSn lasers. However, developing a complementary-metal-oxidesemiconductor (CMOS) compatible approach to prepare GeSn QDs is the main bottleneck at present. In this work, we demonstrate a highly controllable method for the synthesis of GeSn QDs in a CMOS compatible way. Ultra-high area density 2.1 x 10(12) cm(-2), high-Sn fraction 44.2%, and narrow distributed size of the GeSn QDs is obtained. Furthermore, evident quantum confinement effect is observed from the absorption and room-temperature photoluminescence spectra. The properties of the GeSn QDs can well be controlled by merely adjusting the preparation temperature. Moreover, the synthesis mechanism of the GeSn QDs is comprehensively analyzed and revealed using classical nucleation theory and first-principles calculation. The feasible and CMOS compatible method with high controllability may provide a promising way to obtain highly efficient Si-based light emitting materials, and may further be applied in other group-IV alloys, such as SiSn, SiGeSn, SiPb, and GePb.

Automated summary

In this study, a highly controllable method for synthesizing GeSn quantum dots in a CMOS compatible way was demonstrated, resulting in high area density, high-Sn fraction, and narrow size distribution of the GeSn quantum dots. The properties of the GeSn quantum dots can be well controlled by adjusting the preparation temperature.