ZnO-based photoconductive UV detector

Wide band gap ZnO(E-g=3.37 eV @,RT)-based photoconductive UV detector was simply fabricated arid characterized. The undoped-ZnO thin films with 0.5 pro thickness were grown on sapphire single crystal substrate by RF magnetron sputtering. The resistivity of ZnO thin film were about 300 Omega.cm. As ohmic metals, Au and Al were deposited on the ZnO film by thermal evaporation, and the IN characteristic curve was examined. In case of Au contacts the IN measurement showed a better ohmic behavior than Al. Spectral photoresponse was measured as the wavelength was varied from. Photocurrent was not changed in the visible range, but showed the maximum at lambda=375 nm. At the bias of 1 and -1 V between the electrodes, the spectra were symmetric. Dark current in the MSM photoconductive UV detector was 10(3) less than the photocurrent at lambda=375 nm in the bias voltage of -3V to 3V.