Influence of doping concentrations on the aluminum doped zinc oxide thin films properties for ultraviolet photoconductive sensor applications

Aluminum (Al) doped zinc oxide (ZnO) thin films have been prepared on microscope glass substrate using sol–gel spin-coating method with different doping concentrations from 0 to 3 at.%. The thin films were characterized using X-ray diffractometer (XRD), UV–vis-NIR spectrophotometer, Current–Voltage (I–V) measurement system and photocurrent measurement system for applications in ultraviolet (UV) photoconductive sensor. From the XRD analysis, increasing of doping concentration affected structural properties of the thin film where c-axis orientation becomes weaker. UV–vis-NIR spectra reveals all films exhibit high transmission (>80%) in UV-NIR region. Improvement in electrical properties with dopant concentrations is observed as shown by I–V measurement results. 1 at.% Al doped ZnO thin film shows the highest photocurrent value after irradiated with UV lamp (365 nm).