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

Recent progress on (Si)GeSn optoelectronic devices holds great promise for photonic integration on Si substrates. In parallel to the development of bulk devices, (Si)GeSn-based quantum wells (QWs) have been investigated, aiming to improve device performance. While multiple QW structures are preferred for the device applications, a single quantum well (SQW) is more suitable for optical property studies. In this work, a comprehensive study of an SiGeSn/GeSn SQW was conducted. The calculated band diagram provided band alignment and energies of possible transitions. This SQW features a direct bandgap well with L–Γ valley energy separation of 50 meV, and 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 a better understanding of the SQW optical properties. This study could provide guidance for advancing the future QW design toward device applications. [ABSTRACT FROM AUTHOR]