Annealing Effects on the Structural, Optical, and UV Photoresponse Properties of ZnO Nanostructures Prepared by RF-Magnetron Sputtering at Different Deposition Temperatures

Abstract

Undoped ZnO nanostructures were deposited on SiO 2 /Si substrates via radio frequency magnetron sputtering at different deposition temperatures (room temperature, 200, 300, and 400°C). The prepared samples were annealed at 500°C for 2 h under an N 2 flow. The structural, surface morphological, optical, and photoresponse characteristics of ZnO nanostructures as deposited and after annealing were then investigated. The energy bandgaps of all samples after annealing (3.22-3.28 eV) decreased compared with those of the as-deposited specimens. The barrier height increased when the deposition temperature increased and reached 0.77 eV at 400°C after annealing with a leakage current of 0.17 lA at a 5 V bias. The UV photodetector device which was deposited at the optimal temperature of 300°C, has 12.51 9 10 3 % photosensitivity, 2.259 lA dark current, 0.508 s response time, and 0.466 s recovery time. The dark current significantly decreased for all samples after annealing. The proposed UV photodetectors exhibit high performance, high photosensitivity, shorter response and recovery times, and excellent stability at lower bias voltages of 5 and 2 V.

Optical properties of Gd3+-doped ZnO:SiO2 thin films

“…Thus, in [34] for ZnO films obtained by the sol-gel method, the value of E g was 2298 eV, and for ZnO films doped with gold obtained under the same conditions, the value of E g was from 3307 to 3325 eV. In [35] for ZnO films obtained by magnetron sputtering on SiO 2 /Si substrates, the value of E g was 3.22-3.28 eV.…”

Fast Degradation of Green Pollutants Through Nanonets and Nanofibers of the Al-Doped Zinc Oxide

“…Daneshvar et al [11] reported that the complete decay of acid red 14 was successfully achieved by the ZnO-based photocatalyst. Other researchers revealed that the photocatalytic activity of ZnO is higher than that of TiO 2 [12,13]. However, Wang et al [14] and Zhou et al [15] claimed that ZnO as a photocatalyst has some problems such as a low quantum yield in the photocatalytic reactions in aqueous solutions and the fast recombination rate of electron-hole pair, which obstruct commercialization of the photocatalytic degradation process.…”

Tuning the Structural and Optical Properties of SILAR-Deposited Cu2O Films Through Zn Doping

“…Cuprous-oxide-nanostructured thin films have been prepared by several methods, like chemical vapor deposition [13], pulsed laser deposition [14], sputtering [15], spray pyrolysis [16], thermal evaporation [17], and electrodeposition [18], and expensive equipments and rigorous operational conditions are needed in the above methods. Moreover, these techniques require high temperatures for the deposition of cuprous oxide, whereas certain lowtemperature methods yield promising copper oxide films with high absorption coefficient which can consequently offer good conversion efficiency in solar cells.…”