Ultraviolet photoconductivity and photoluminescence properties of spray pyrolyzed ZnO nanostructure: Effect of deposition temperature

The current investigation focuses on the influence of substrate temperature on Zinc Oxide (ZnO) thin films synthesized on glass substrates using 0.1 M precursor solution by low-cost spray pyrolysis technique. The x-ray diffraction peaks matched the hexagonal wurtzite structure of ZnO with the highest intensity along the (1 0 1) plane. Estimated the crystallite size, dislocation density, micro-strain, and the number of crystallites in the deposits using X ray diffraction (XRD) data. The crystallinity of the films deposited at 450 degrees C was maximum. Fibrous surface morphology is altered by varying the deposition temperature. The enhancement of optical transmittance and energy bandgap of the deposits with deposition temperature. The reduction of Urbach energy with an increase in the substrate temperature confirmed the improvement of crystallinity. The photoluminescence study revealed peaks associated with electron-hole pair recombination, zinc, and oxygen-related defects. The samples deposited at 450 degrees C showed minimum defects. Commission Internationale de l'e acute accent clairage (CIE) chromaticity diagram showed white light emission for sample deposited at 450 degrees C with the color temperature equal to 5378 degrees C which is agreeing with the temperature of a normal white light source. Improvement of free carrier concentration and n-type conductivity due to the enhancement of crystallinity was observed. ZnO thin films deposited at 450 degrees C showed maximum photocurrent when illuminated with UV light and faster rise and fall of photo resistance due to the improvement in the crystallinity and carrier concentration. The maximum photosensitivity was observed for the samples synthesized at 450 degrees C. Hence the ZnO thin films deposited at 450 degrees C can be used as ultraviolet photodetector material.

Automated summary

This study investigates the influence of substrate temperature on Zinc Oxide (ZnO) thin films synthesized on glass substrates using low-cost spray pyrolysis technique. The results show that the films deposited at 450 degrees C have the best crystallinity and altered surface morphology. The increase in substrate temperature improves the crystallinity and reduces defects. Additionally, the films deposited at 450 degrees C exhibit minimum defects and can be used as ultraviolet photodetector material.