Electrical and infrared responses of n-VO2/p-GaAs heterojunctions based on VO2 phase transition properties

Abstract

In this investigation, high-quality VO2 films were prepared on p-GaAs wafers by DC magnetron sputtering and post-annealing process. The results indicate that the optimum annealing temperature and time of the sample are 2 h and 420 °C with the excellent rectification characteristics originated from the n-VO2/p-GaAs interface before the occurrence of semiconductor-to-metal phase transition in VO2, which can be explained by the thermal electron emission model. The device’s threshold voltage at 30 °C and 60 °C corresponds to 7.5 and 6 V. The responsivity of the as-fabricated photon detector under 980 and 1310 nm laser illumination was 0.013 and 0.022 A W−1 at an applied bias of 3 V as well as 0.0025 and 0.0048 A W−1 at zero bias, respectively. The NIR transmittance decreases with increasing voltage and temperature due to the combination of voltage and temperature to induce VO2 phase transition. The results will be beneficial to explore and improve the IR photon detector based on VO2 and provide ideas for new optoelectronic devices with phase transition characteristics.