A study of Al:ZnO based MSM UV sensors with Ni metal electrodes

This work reports, preparation and characterization of Al doped ZnO (Al:ZnO) based metal-semiconductor-metal (MSM) UV sensors with nickel (Ni) metal electrodes. Radio-frequency magnetron sputtering method was used for depositing Al:ZnO thin films on p-type Si substrates. The structural and elemental composition of the Al:ZnO thin films were investigated by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The XRD spectra indicated that the Al:ZnO thin films had good crystalline quality. The XPS results confirmed the presence of Zn, Al and O elements, in the Al:ZnO thin films. Finally MSM devices were created with metal electrodes of Ni and an active layer of Al:ZnO thin-films. The interdigitated finger contacts of Ni were patterned on Al:ZnO/Si by optical lithography. Two MSM devices with same finger-spacing and width of 15 μm and 30 μm were fabricated in the experiment. The electrical measurements were done for examining the UV-sensing of these devices. These low-voltage MSM UV sensors could be liable for practical applications.