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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]

This paper reports the study of GeSn/GeSn/GeSn single quantum well (SQW) and double quantum wells (DQWs). The quantum well (QW) structures were grown on Ge buffered Si substrates using an industrial standard reduced-pressure chemical vapor deposition system. Pseudomorphically grown structures were observed using x-ray diffraction measurements. Defect-free interfaces between each layer were revealed using cross-sectional transmission electron microscopy. Atomic-scale high-resolution transmission electron microscopy and Fourier transform patterns exhibited the high crystalline quality of QWs. Temperature-dependent photoluminescence (PL) was performed, and the emission peaks attributed to the QW region were identified. The dominant optical transition changed from direct bandgap transition at 300 K to indirect bandgap transition at 10 K. Theoretical calculation showed the type-I band alignment for the QWs. Moreover, the Γ and L valley electron distributions and non-radiative lifetimes were evaluated, which further explained the PL characteristics of the QW samples. [ABSTRACT FROM AUTHOR]