Optical gain and threshold current density for mid-infrared GaSbBi/GaSb quantum-well laser structure

Abstract This work is focused on band structure engineering and optical proprieties of GaSbBi/GaSb type I quantum well mid-infrared laser structure on GaSb substrate. Wherefore, the band alignment is tailored and optoelectronic properties are investigated for the proposed structure based on GaSb1−xBix/GaSb hetero-interfaces in the range of alloy compositions between 0 ≤ x ≤ 0.14 . The electron and holes effective masses are deduced from the expressions extracted from the k.p model. The laser structure is designed to function at 2.7 μm at room temperature (RT), the addition of bismuth into the GaSb active region improve a preferment optical gain and the threshold current density (Jth) including computation of radiative, non radiative and Auger recombination. For typical carrier injection 5 × 10 18 c m - 3 at 300 k peak gain value of the order of 2000 cm−1 are reached and a modal gain equal to 96 cm−1 can be attained. A Jth around1.2 kA/cm2 is expected through moderate optical losses.