Hybrid p-Au@PbI2/n-Si heterojunction photodetector prepared by pulsed laser ablation in liquid

Abstract

In this study, a hybrid Au@PbI2/Si heterojunction photodetector was prepared by laser ablation in liquid technique at different number laser pulses. The electrical properties of Au@PbI2/Si heterojunction were measured as a function of the number of laser pulses. The dark current-voltage characteristics showed that fabricated heterojunctions exhibited rectification properties and the largest value of rectification factor at 5 V bias was ˜35 for heterojunction prepared at 100 laser pulses. Hall effect measurements reveal that all synthesized Au@PbI2 have p-type conduction and its Hall mobility decreases as the number of laser pulses increase. The ideality factor and the turn-on voltage of heterojunctions were determined as a function of the number of laser pulses. Capacitance-voltage characteristics of the heterojunctions confirm that all the heterojunctions are abrupt and the value of built-in-potential was ranged from 0.3 to 0.8 V depending on the number of laser pulses. The effect of the number of laser pulses on the figures of merit of the hybrid Au@PbI2/Si heterojunction photodetector namely; responsivity, external quantum efficiency, detectivity and minority carrier lifetime was studied. The responsivity of the photodetector shows a presence of two response peaks located at visible and near-infrared regions which are related to the absorption edge of Au@PbI2 nanoparticles and bulk silicon. The energy band diagram of hybrid Au@PbI2 nanocomposite under illumination condition prepared at 100 laser pulses was constructed.