Al doped ZnO based metal–semiconductor–metal and metal–insulator–semiconductor–insulator–metal UV sensors

Abstract

The paper reports the fabrication and characterization of Al doped ZnO (Al:ZnO) based metal–semiconductor–metal (MSM) and metal–insulator–semiconductor–insulator–metal (MISIM) ultraviolet sensors (Ss). The Al:ZnO thin film was grown on a p-type Si substrates by RF-sputtering method and palladium (Pd) was used as interdigitated metal electrodes for the MSM and MISIM devices. Approximately 5nm thick layer of SiO2 were deposited above Al:ZnO thin film for MISIM devices. The I–V characteristics of MSM and MISIM devices with finger-spacing of 5μm were measured under dark and under ultraviolet (UV) light. It was found that Iphoto/Idark values were 0.893×102 and 1.735×103 also the measured responsivities were 0.0411 and 0.0155A/W for MSM and MISIM UV sensors (UVSs), respectively. These devices can find applications in various electronic and optoelectronic systems.