Abstract
The effects of Mg on the microstructural, optical, and electrical properties of sol-gel derived ZnO transparent semiconductor thin films and the photoelectrical properties of photodetectors based on MgxZn1−xO (where x = 0 to 0.3) thin films with the metal-semiconductor-metal (MSM) configuration were investigated in this study. All the as-synthesized ZnO-based thin films had a single-phase wurtzite structure and showed high average transmittance of 91% in the visible wavelength region. The optical bandgap of MgxZn1−xO thin films increased from 3.25 to 3.56 eV and the electrical resistivity of the films rose from 6.1 × 102 to 1.4 × 104 Ω·cm with an increase in Mg content from x = 0 to x = 0.3. Compared with those of the pure ZnO thin film, the PL emission peaks of the MgZnO thin films showed an apparent blue-shift feature in the UV and visible regions. The photo-detection capability was investigated under visible, UVA, and UVC light illumination. Linear I-V characteristics were obtained in these ZnO-based photodetectors under dark and light illumination conditions, indicating an ohmic contact between the Au electrodes and ZnO-based thin films. It was found that the pure ZnO photodetector exhibited the best photoconductivity gain, percentage of sensitivity, and responsivity under UVA illumination. Under UVC illumination, the photoconductivity gain and percentage of sensitivity of the MgZnO photodetectors were better than those of the pure ZnO photodetector.
Highlights
Solid-state photodetectors based on wide bandgap semiconductors, such as GaN, ZnO, SiC, and Diamond, are especially attractive for ultraviolet (UV) radiation detection
Six diffraction peaks were identified by comparison with the Joint Committee for Powder Diffraction Standards (JCPDS) card No 036-1451 for corresponding the Joint Committee for Powder Diffraction Standards (JCPDS) card No 036-1451 for corresponding to the (100), (002), (101), (102), (110), and (103) crystallographic planes of ZnO crystal
Analysis of XRD data revealed that the full widths at halfmaximum (FWHMs) for the three major diffraction peaks, (100), (002), and (101), increased with these as-synthesized metal oxide thin films were polycrystalline in nature, confirming the formation of a single-phase hexagonal wurtzite structure
Summary
Solid-state photodetectors based on wide bandgap semiconductors, such as GaN, ZnO, SiC, and Diamond, are especially attractive for ultraviolet (UV) radiation detection. Their investigation and development open up potential applications in fields as varied as environmental protection, medicine and healthcare, space communication and exploration, optoelectronic circuits, and military surveillance [1,2,3]. It is general knowledge that when a semiconductor material is exposed to solar radiation, the photon energy creates electron-hole pairs inside the material, and the charges can be subsequently collected to produce electrical signals. The tailoring of optical properties (especially the bandgap energy) of crystalline semiconductor materials could lead to a broad-spectral response of detection for photodetectors and expand their application fields [4]. Chemical, and mechanical stability at room temperature make it attractive for use in electronics, optoelectronics, and renewable energy generation [5,6]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
