Preparation of high-performance p-CuO/n-Si heterojunction photodetector by laser-assisted chemical bath deposition: Effect of laser wavelength

In this study, a copper oxide thin film was prepared by the CW laser assisted-chemical bath deposition (LACBD) technique. The effect of laser wavelength on the structural, optical, and electrical properties of CuO film was investigated. The X-ray diffraction (XRD) study shows that the deposited CuO films are crystalline with a monoclinic structure. The optical energy gap increases with the use of a laser during film preparation, and it varies from 2.3 to 1.9 eV. The scanning electron microscope (SEM) images confirm that the morphology of the film was dependent on the laser wavelength. Increasing the laser wavelength results in decreasing the grain size of the film and enhancing the crystallization. Energy dispersive X-ray analysis confirms the presence of copper and oxygen elements. Hall measurement revealed that the deposited films are p-type and that the electrical conductivity and mobility increased with the use of a laser. The current-voltage characteristics of the p-CuO/n-Si heterojunction were studied in the dark and under illumination. The maximum photocurrent was found for a photodetector prepared with a laser wavelength of 550 nm. The spectral responsivity revealed that the photodetectors exhibit two peaks of response at 450 nm and 800 nm. The maximum responsivity reached was 0.44 A/ W at 450 nm and 0.65 A/W at 800 nm for a photodetector prepared at the laser wavelength of 550 nm at bias voltage of -5 V. The external quantum efficiency and specific detectivity of the p-CuO/n-Si heterojunction photodetector prepared at a laser wavelength of 450 nm were 1.2 x 10(2)% and 1.46 x 10(12) Jones, respectively. The aging effect on the figures of merit of the photodetectors is studied. The rise and decay times of the photodetectors are estimated.

Automated summary

In this study, a copper oxide thin film was prepared using the CW laser assisted-chemical bath deposition (LACBD) technique. The effect of laser wavelength on the structural, optical, and electrical properties of CuO film was investigated. Increasing the laser wavelength resulted in decreasing the grain size of the film and enhancing the crystallization. The p-CuO/n-Si heterojunction photodetectors exhibited two peaks of response at 450 nm and 800 nm.