Synthesis and Characterization of High c-axis ZnO Thin Film by Plasma Enhanced Chemical Vapor Deposition System and its UV Photodetector Application

Abstract

In this study, zinc oxide (ZnO) thin films with high c-axis (0002) preferential orientation have been successfully and effectively synthesized onto silicon (Si) substrates via different synthesized temperatures by using plasma enhanced chemical vapor deposition (PECVD) system. The effects of different synthesized temperatures on the crystal structure, surface morphologies and optical properties have been investigated. The X-ray diffraction (XRD) patterns indicated that the intensity of (0002) diffraction peak became stronger with increasing synthesized temperature until 400 (o)C. The diffraction intensity of (0002) peak gradually became weaker accompanying with appearance of (10-10) diffraction peak as the synthesized temperature up to excess of 400 (o)C. The RT photoluminescence (PL) spectra exhibited a strong near-band-edge (NBE) emission observed at around 375 nm and a negligible deep-level (DL) emission located at around 575 nm under high c-axis ZnO thin films. Field emission scanning electron microscopy (FE-SEM) images revealed the homogeneous surface and with small grain size distribution. The ZnO thin films have also been synthesized onto glass substrates under the same parameters for measuring the transmittance. For the purpose of ultraviolet (UV) photodetector application, the interdigitated platinum (Pt) thin film (thickness ~100 nm) fabricated via conventional optical lithography process and radio frequency (RF) magnetron sputtering. In order to reach Ohmic contact, the device was annealed in argon circumstances at 450 (o)C by rapid thermal annealing (RTA) system for 10 min. After the systematic measurements, the current-voltage (I-V) curve of photo and dark current and time-dependent photocurrent response results exhibited a good responsivity and reliability, indicating that the high c-axis ZnO thin film is a suitable sensing layer for UV photodetector application.

Cytotoxic activities of zinc oxide nanoparticles on non-invasive human breast and prostate cancer cell lines

“…In this study the ZnO-NPs have shown a strong cytotoxic activity on both cancer cell types in vitro. Results of our study were consistent with indings of previous studies (Wang et al, 2018;Chao and Wei, 2015;Król et al, 2017).…”

“…The cytotoxic activity of ZnO-NPs is associated with ROS production. (Wang et al, 2018) and (Chao and Wei, 2015) reported that ZnO-NPs had displayed their anticancer properties due to their intracellular ability to stimulate the formation of ROS in high level within the tumor cells.…”

Internal stress induced natural self-chemisorption of ZnO nanostructured films

“…Until now, many research works have been reported about the hydrophobic/hydrophilic reversible process caused by light-controlled method for ZnO-based nanostructures 17 18 19 20 . ZnO has direct wide band gap (3.37 eV), high exciton binding energy (60 meV) and optical transparency in the visible light, thus, ZnO is an expected material for many novel applications, for example, piezoelectric transducers, transparent thin film transistors, chemical biosensors 21 22 , solar cells and ultraviolet (UV) detectors 23 24 25 . According to the above functionalities, ZnO can provide a hydrophobic surface, which may be transformed to hydrophilic surface by UV irradiation, coexists with intrinsic semiconductor properties and a particular surface morphology.…”

Compositional, Structural, Morphological, and Optical Properties of ZnO Thin Films Prepared by PECVD Technique

“…Due to these promising properties, we were interested in the synthesis and growth of ZnO thin nanostructured films, which can increase their electrical properties [19][20][21]. ZnO nanostructured films can be obtained by several methods which can be of physical type such as radio frequency magnetron sputtering [22,23], electron beam evaporation [24,25], pulsed laser deposition [26,27], molecular beam epitaxy (MBE) [28,29], or of chemical type as spin coating [30,31], dip coating [32,33], spray pyrolysis [34,35], chemical vapor deposition (CVD) [36,37] and plasma-enhanced chemical vapor deposition (PECVD) [38,39]. Out of these, PECVD is of particular interest due to its simplicity, lack of need for ultra-high vacuum requirement, and its capability of deposing films of good crystalline quality.…”