Surface plasmon-enhanced p-type MSM UV photodetector using gold quantum dots

Abstract

A novel surface plasmon-enhanced MSM UV photodetector (PD) was fabricated by sputtering (< 5 nm) gold Quantum dots (QDs) on the surface of the active layer of Sb doped ZnO nanostructures. The nanostructures were grown on ITO/PET substrates using Sol-gel and low-temperature hydrothermal methods. The MSM contacts were deposited using thermal evaporation technique. The influence of the plasmonic layer on the PD was studied by performing structural (HRTEM, EELS, and XRD) and electrical studies (IV curves without and with UV light of 365 nm, stability and dynamic response). Hall measurements were performed on the device and the device was found to have a hole concentration of 1.0224 × 1020/cm3 and Hall mobility of 2231 cm2/ (V.s). Upon exposure to UV light of 365 nm, the surface plasmon polaritons are scattered by gold QDs, leading to the creation of hot-holes that can cross into the active layer of Sb doped ZnO nanostructures, where they are collected as the photocurrent. The device exhibited high performance with the dark current as 3.92 mA and photocurrent as 148 mA, at 5 V of applied bias. The PD also showed very high responsivity and External Quantum Efficiency (EQE) of 5.67A/W and 1.93 × 103%, respectively. The ratio of photocurrent to dark current was 37.75. These values prove that the device had a high response to UV illumination