Keywords:GeSn, quantum well, absorption
Narrow-bandgap GeSn material system has emerged as a promising platform for efficient Si-based infrared photodetectors (PDs) for a wide range of applications. The realization of high-quality, high Sn-content GeSn alloys using low-temperature growth techniques has led to the development of GeSn-based PDs with extended photodetection range. Here we present a study of the growth and optical characterization of GeSn/Ge multiple-quantum-well (MQW) structures on silicon for efficient PDs on silicon. Clear step-like absorption and excitonic features in responsivity spectrum were observed, confirming quantum-confirment in this novel GeSn/Ge quantum well structure.