UV photodetector study based on Ce: ZnO nanostructures with different concentration of Ce dopant

Abstract

UV photodetectors (PDs) find pivotal roles across diverse domains like space exploration, radiation monitoring, and electronics. Zinc oxide (ZnO), an n-type semiconductor with a wide bandgap, stands out as an attractive material for photodetection due to its remarkable UV responsivity. This study centers on assessing the role of Ce doping in enhancing the UV sensitivity of ZnO-based photodetectors when subjected to laser illumination (excitation wavelength: 374 nm). Synthesized through a hydrothermal approach, Zn1-xCexO nanostructures with varying concentrations (x = 1.5, 3.5, 5.5, and 7.5 wt%) were subsequently deposited onto ZnO nanorods (NRs) via tape casting. A comprehensive array of characterization techniques was employed to analyze the structural, morphological, and optoelectrical properties of Ce:ZnO. Incorporating Ce to ZnO lattice induced a reduction in the density of oxygen vacancies, culminating in an enhancement of optoelectronic performance. This improvement encompassed aspects such as photocurrent and responsivity within a p-n heterojunction Ce: ZnO–Cu2O (CZC) UV-PD setup. The introduction of cerium led to a slight shift in the band gap energies, from 3.18 eV for pristine ZnO to 3.23–3.19 eV for the CZ samples. Impressively, Ce-doped ZnO (5.5 wt%) nanostructures exhibited enhanced performance in UV detection, showcasing a detectivity of approximately ∼42 × 109 (Jones), an expedient rise time of under 0.1 s, and a desirable decay time of 8.7 s for the CZC-3%.