Composition‑Dependent Defect Formation Energies in InAs_1-xSb_x with Comparisons to InAs

Infrared (IR) detectors measure the photocurrent induced by the incident radiation that promotes electrons from occupied into unoccupied states. Photocurrent generation is controlled by the energy gap between these two states and is a property of the host material. Therefore, altering the host, for example through alloying, can be used to optimize detectors for targeted radiation types. In this presentation, we focus on InAs alloyed with Sb as a pathway to decrease the bandgap for detection of a wider range of IR radiation. We use a Hubbard-U+V extension to standard Density-Functional-Theory (DFT) to explore In(As, Sb) alloy formation energies and its effects on electronic structure and bandgap. Our preliminary results show that the bandgap decreases from 0.30 eV to 0.05 eV as the Sb concentration increases from 0at% to 12.5at% in our 64-atom simulation cells. We will discuss the energetics of dopant clustering, defect formation energies, and evaluate the potential implications for electronic recombination pathways in In(As,Sb) alloys, that are relevant to IR detector operation and reliability. SNL is managed and operated by NTESS under DOE NNSA contract DE‑NA0003525.