Optical and structural properties of GeSn/SiGeSn multiple quantum wells for infrared optoelectronics

We have investigated the correlation between structural and defect properties, optical performance of GeSn/SiGeSn multi-quantum well (MQW) structures as a function number QWs. Our results show that significant diffusion intermixing occur at interfaces during sample growth. The is more pronounced larger depths below surface where Sn Si composition profile in QWs layers undergoes transition from block-shaped to compositionally graded Λ-shaped profile. Simultaneously, peak concentration reduces with depth up 2.0 ± 0.2 at.% while integrated photoluminescence (PL) significantly degraded. reduced PL emission both GeSn buffer attributed increasing density non-radiative recombination centers MQWs due alloy disordering diffusion. use layer reference shown be important analyze SiGeSn/GeSn generally (Si)GeSn materials.