Fast-response IWO/Si heterojunction photodetectors

Abstract Indium tungsten oxide (IWO)/Si-based heterojunction photodetectors are designed with optimized structure, and they exhibit enhanced photoelectric detection capabilities. Under the action of the self-built electric field, the current easily flows from IWO to Si, but the resistance is high when flowing in the reverse direction due to the presence of the electron barrier. Under the 450 nm illumination condition, the effect of light on the forward flow from IWO to Si is minimal, but the illumination is sufficient to generate a large number of photogenerated carriers, which separate under the action of the built-in electric field and form a distinct photocurrent under the applied bias voltage. The optimized device exhibited ultra-fast response times (rise time of 8.2 ms and fall time of 7.9 ms), along with a high normalized detectivity ( D * = 4.73 × 10 11 cm·Hz(½)/W) and a high photoswitch ratio (PS = 6.6 × 10 3 ). These results demonstrate that the IWO/Si photodetector can serve as a high-performance photodetection device and is one of the candidates that exhibit more easily reproducible and stable performance compared to photodetectors based on two-dimensional materials.