Al doping and defect regulation of sputtered CdZnTe films based on Al–AlN transition layers

Abstract

CdZnTe films with less defects and high quality were fabricated on aluminum-rich AlN (Al–AlN) transition layers by RF magnetron sputtering technique. The Al doping and regulation effect on defect states, structure and photoelectrical performance of CdZnTe films were minutely investigated by XRD, HRTEM, SEM, XPS, Photoluminescence and Photoelectric characteristics. Results strongly suggested the self-doping process of Al from Al–AlN transition layers, which helped to compensate the defect density of Cd vacancy in CdZnTe films, thus improving crystallization, response performances and resistivity of Al-doped CdZnTe films. Electrical characterization implied the formation of good ohmic contact between electrodes and Al-doped CdZnTe films. Under 254 nm UV light illumination, the surface dark current of optimal Al-doped CdZnTe film was 25 times smaller than that of non-doped film, and rise and decay times were 3.4 and 2.8 times faster, indicating the feasibility of high quality film detectors for solar-blind UV detection.