Performance evaluation of InAs/GaSb superlattice photodetector grown on GaAs substrate using AlSb interfacial misfit array
We report on the growth and opto-electronic characterization of type-II InAs/GaSb superlattice (SL) mid-wavelength infrared pin photodetector grown on a GaAs substrate. AlSb interfacial misfit array was employed at the GaAs buffer/GaSb epilayer interface to reduce the dislocation density of the SL structure grown on the lattice mismatched GaAs substrate. Optical and electrical performance of this sample (SL-GaAs) were then compared with the reference sample of the same structure grown on a GaSb substrate (SL-GaSb). At 80 K, the dark current density and the detectivity values of the pin photodetectors were recorded as 5.40 × 10−3 A cm−2 and 2.34 × 1010 cm Hz0.5 W−1 for the SL-GaAs and 9.50 × 10−4 A cm−2 and 4.70 × 1010 cm Hz0.5 W−1 for the SL-GaSb, respectively.