Improvement Of The Photoresponse Of The Solar Blind ZnO Photoconductive UV Detector

Abstract: The UV solar blind photoconductive detector was fabricated using ZnO film prepared by thermal chemical spray pyrolysis technique. The ZnO thin film was grown on quartz substrate heated to 400 ºC. The studies of the films structure and optical properties showed that the films are n- type with optical band gap of around 3.1-3.3 eV.The aluminum Interdigitated electrodes were evaporated on the film to fabricate the UV photoconductive detector. The photoresponsivity was measured under illumination of the ZnO film by 1 mwatt, 385nm UV radiation from GaN UV- led and it was 2.24 A/W. The photoresponse enhancement was improved by coating the ZnO film with 200 nm of PVC, PVA, and polyamide polymers using spin coating technique. The polymer nanolayer highly increased the photoresponse of the fabricated ZnO UV detector to a factor of 104 with respect to the uncoated ZnO film. The results show that the ZnO film coated with polyamide polymer gives the highest responsivity rather than the PVA and PVC polymers. Keywords:UV detector, ZnO thin film, polymer ZnO composite, spray pyrolysis