Fabrication And Structure Optimization Of Zno-based UV Photodetectors

ZnO is a wide direct band gap materials(~3.37 eV at room temperature) featuring environment friendliness, extensive distribution and radiation hardness. Via alloying with MgO, the band gap energy of MgZnO can be controlled from 3.3 eV to 7.8 eV. ZnO-based thin film and the device performances have received abroad attention. In this paper, the growth of ZnO-based thin film and the fabrication of ZnO-based ultraviolet(UV)photodetectors(PDs) have been detailed. In order to enhance the performances of the PDs,the quality of the film and the structure of the device have been optimized. The main researches are as follows:(1) The crystalline and optical performances of the ZnO-based film have been researched, which was grown on the quartz substrate(Si O2) by radio-frequency(RF)magnetron sputtering technology. The performances of the metal-semiconductor-metal(MSM) structured PDs have been measured and study, which was based on the ZnO-based film.(2) The MSM structured Mg0.2Zn0.8O PD was annealed in a tube furnace. The performances of the device have been characterized by the X-ray diffraction(XRD) spectra,the PerkinElmer Lambda 950 UV/VIS spectrometer, the Zolix DR800-CUST testing system and the semiconductor analyzer(Agilent 16442 A Test Fixture). The responsivity suddenly increases at 700 °C as the results illustrated.(3) The UV PDs based on double-layer films have been fabricated, in which the film was grown by the RF magnetron sputtering technology. The fundamental structured perfect the fundamental physics and controlled the response wavelength shifting.(4) To overcome lower responsivity and higher dark current, the optimized ZnO/Au/ZnO sandwich structured PDs have been design, which combing low dark current and high responsivity(enlarged ~60 times).