GaAs/GeSn/Ge n–i–p diodes and light emitting diodes formed via grafting

Germanium-tin (GeSn) is a promising semiconductor material for future optoelectronic devices operating at the near-infrared to mid-infrared spectral range. In this work, we report the synthesis and characterization of a GaAs/GeSn-MQW/Ge n–i–p heterojunction created via grafting. The improved energy barriers between GaAs and GeSn-MQW enable the diodes fabricated from the heterojunction to exhibit extraordinary rectification ratios (larger than 105) and record-low reverse-bias current density (∼10−6 A/cm2). The grafting-based LED performs as well as the epitaxially grown counterpart. The work may pave the way for future improvements of GeSn-based electronic devices.