Influence of AZO buffer layer on characteristics of ZnO film on Glass Substrates for Schottky UV photodetector applications

An Al-doped ZnO (AZO) thin film was introduced into the structure of Ag/ZnO schottky Photo detectors (PDs) prepared by magnetron sputtering method on glass substrates. Influences of AZO layer on characteristics of ZnO film and performances of Ag/ZnO schottky PDs were discussed in detail. Results investigated by means of the scanning electron microscopy (SEM), X-ray diffraction (XRD) and Photoluminescence (PL) spectra show that the introduction of an AZO buffer layer can effectively decrease the defects and improve the crystallization of the ZnO thin film. Compared with Ag/ZnO schottky PDs, the Ag/ZnO/AZO PDs possess more excellent rectifying characteristics, the photocurrent(Iph) to dark current(Id) ratio are improved from 6.4 to 100.7. Given the bias voltage at -2V, the photoresponsivity R and detectivity D* are increased from 0.15 AW-1 and 4.08×1010 Jones to 0.69AW-1 and 3.78×1011 Jones, respectively. The response speed becomes faster, the response and delay times are decreased from 281 and 395ms to 178 and 300ms, respectively. The results provide a new idea for the preparation of high performance ZnO film UV PDs on low-cost glass substrates.