Effects of incident-light-intensity-dependent band gap narrowing on barrier heights of p-doped AlxGa1−xAs/GaAs heterojunction devices

• Light-intensity causes zero VB offsets in low-barrier IR detectors at T > 50 K.
• PL shows band gap increase in undoped GaAs with illumination at T = 25 K.
• Undoped GaAs and p-AlGaAs are reluctant to BGN caused by incident light intensity.
• Undoped GaAs/p-doped Al0.01Ga0.99As combination suitable for FIR/THz detectors.

Band gaps of semiconductor materials are reduced due to band gap narrowing (BGN). Photoluminescence measurements on GaAs and AlGaAs thin films revealed a dependency of incident light intensity, and temperature in BGN in addition to the doping density. As a result, the valence band offset of p-doped GaAs/AlGaAs heterojunctions were reduced under illumination and high temperatures. We present evidence of incident-light-intensity causing barrier reduction at temperature >50 K causing zero valence band offsets in low-barrier heterostructures such as p-GaAs/Al0.01Ga0.99As, in addition to the dark-current increase by thermal excitations, causing the device failure at high temperatures.