Study of SiGeSn/GeSn single quantum well towards high-performance all-group-IV optoelectronics.

The recent progress on (Si)GeSn optoelectronic devices holds a great promising for photonic integration on the Si substrate. In parallel to the development of bulk devices, the (Si)GeSn based quantum wells (QWs) have been investigated aiming to improve the device performance. While the multiple QW structure is preferred for the device application, the single quantum well (SQW) is more suitable for optical property study. In this work, a comprehensive study of a SiGeSn/GeSn SQW was conducted. The calculated band diagram provided the band alignment and energies of possible transitions. The SQW features the direct bandgap well with L-{\Gamma} valley energy separation of 50 meV, and the barrier heights for both electron and hole are greater than 80 meV. Using two continuous-wave and two pulsed pumping lasers, the analysis of PL spectra allows for identifying different transitions and for better understanding the SQW optical properties. The study could provide the guidance for advancing the future QW design towards device applications.