Tensile-strained GeSn/Ge rolled-up nanomembrane with enhanced photoluminescence

We present the development of a rolled-up GeSn/Ge nanomembrane designed to enhance its photoluminescence (PL). The fabrication process involves growing a GeSn/Ge/Si heterostructure on a silicon-on-insulator (SOI) substrate, followed by selective etching to release the nanomembrane. This process results in a rolled-up configuration, which not only relaxes the compressive strain but also achieves tensile strain on the GeSn layer, confirmed by Raman measurements. PL measurements exhibit a redshift in emission peak from 2361 to 2719 nm, indicating a reduction in bandgap energy to 0.456 eV. Additionally, PL intensity increases by 160% compared to the as-grown sample, highlighting the enhanced light emission efficiency owing to enhanced directness of bandgap by tensile strain.