Schottky barrier lowering in n-AlGaAs/GaAs/AlGaAs double heterojunctions by local light illumination

Abstract We investigated the wavelength dependence of the Schottky photocurrent ( I SG ) in an n-AlGaAs/GaAs/AlGaAs double heterojunction under local light illumination. I SG was measured with the illumination from two light sources (Lights A and B). Light A illuminated the entire Schottky gate region at 60 μW mm −2 with varying the wavelength (940, 975, and 1064 nm), while Light B (670 nm laser) locally illuminated the ungated region at power levels ( P B ) ranging from 0 to 2.9 μW. At low P B (≤86 nA) and high P B (≥0.14 μW), I SG increases and decreases, respectively, with increasing photon energy of Light A. Analysis of the experimental data using a hot carrier model, attributed this behavior to the Schottky barrier lowering induced by Light B. The reduction in the effective Schottky barrier height increases with increasing P B , reaching about 0.5–0.6 eV.