Metamorphic growth of 0.1 eV InAsSb on InAs/GaAs virtual substrate for LWIR applications
Seungwan Woo, Eungbeom Yeon, Rafael Jumar Chu, Jihoon Kyhm, Hoki Son, Ho Won Jang, Daehwan Jung, Won Jun Choi
Abstract
Epitaxial growth of bulk InAs1-xSbx layer on GaAs substrate could open an opportunity for cost-competitive long-wavelength infrared sensors. Achieving this requires a high-quality metamorphic InAsSb layer with a uniform strain relief buffer design. We report a comprehensive analysis of metamorphic InAsSb layers grown on InAs/GaAs virtual substrate for 0.1 eV low bandgap material with an optimized growth condition and group-V flux control. We find that InAsSb surface roughens significantly with increasing Sb composition up to 58%. Lowering the growth temperature of InAsSb layers from 450 ℃ to 425 ℃ mitigated surface roughening while allowing greater than 90% strain relaxation. Moreover, we also present a dramatically increasing threading dislocation density by more than 200 times as a consequence of high Sb composition. Finally, we demonstrate a narrow energy bandgap of 0.13 eV at 10 K in the InAs0.42Sb0.58 layer, which is close to 0.1 eV at room temperature. This InAsSb film grown on InAs/GaAs template paves the way for long-wavelength infrared optoelectronics applications.