Nanostructuration and band gap emission enhancement of ZnO film via electrochemical anodization

Abstract

A C C E P T E D M A N U S C R I P T ACCEPTED MANUSCRIPT2 We report fabrication of nanostructured zinc oxide (ZnO) thin films with improved optical properties through electrochemical anodization. The ZnO films were produced over silicon substrates via radio-frequency (RF) plasma magnetron sputtering technique followed by electrochemical treatment in potassium sulfate solution. After electrochemical treatment, the effect of applied potential on the band gap emission behavior of ZnO films was investigated for the potential drop of 1.8, 2.4 and 3.0 V against reference electrode of Ag/AgCl/0.1M KCl. Depending on these values, ZnO films with different degrees of nonporous morphology, improved structural quality and oxygenrich surface chemistry were obtained. The treatment also resulted in enhancement of band gap emission from ZnO films with the degree of enhancement depending on the applied potential. As compared to the as-deposited films, a maximum increase in the photoemission intensity by more than 2.2 times was noticed. In this paper, any changes in the structure, surface chemistry and band gap emission intensity of the RF sputter deposited films, as induced by the anodization treatment at differential potential values, are discussed.

Orange/Red Photoluminescence Enhancement Upon SF6 Plasma Treatment of Vertically Aligned ZnO Nanorods

“…With a direct band gap and high exciton binding energy values of 3.3 eV and 60 meV, respectively, the transparent n-type semiconductor zinc oxide (ZnO) has demonstrated use for numerous electronic, electrochemical, optoelectronic, and electromechanical devices [1,2,3,4], including light-emitting diodes [5], piezoelectric nanogenerators [6], field emission devices [7], high-performance nanosensors [8,9], solar cells [10,11], and ultraviolet (UV) lasers [12]. Due to their high surface-to-volume ratio and surface area, the ZnO nanostructures with zero- (quantum dots and ultrafine nanoparticles), one- (tubes, rods, belts, and wires), or two-dimensional morphology (sheets, flakes, and thin films) offer superior performance attributes than those of bulk ZnO structures.…”

A comparative study on structural, morphological and photocatalytic properties of anodically grown ZnO nanowires under varying parameters

“…ZnO, with a wide band gap (3.37 eV) and large exciton binding energy (60 meV) [10][11][12][13], has found a wide range of possible applications in photocatalysis [14], photovoltaics [15], lightemitting diodes [16], sensing [17] and many others [18].…”

Formation of ZnO nanowires by anodization under hydrodynamic conditions for photoelectrochemical water splitting

“…In addition, it has a high electrochemical coupling coefficient [7], thermal stability [1,6], high photostability [7], low-cost [11], low toxicity [7,12,13] and biodegradability [14]. All these properties make zinc oxide a promising material for several applications, including catalysis [5], photocatalysis [2,3,6,12], photovoltaics [3], solar cells [2,5,6,11,12,[15][16][17][18], photoelectrochemical (PEC) water splitting for hydrogen generation [11,17], ultraviolet (UV) light-emitting diodes [2,3,6,15,18], ultraviolet lasers [6,12], sensing [2,3,5,6,11,12,14], and so on.…”

“…Until now, several effective methods to prepare ZnO nanostructures have been used: hydrothermal methods [2,[4][5][6]11,14,15], thermal evaporation [6], chemical vapour deposition (CVD) [2,[4][5][6]14,20], pulsed laser deposition (PLD) [2,14], molecular beam epitaxy (MBE) [2,6], template-assisted methods [2,15], metal organic chemical vapor deposition (MOCVD) [6], atomic layer deposition (ALD) [5], sol-gel chemistry [5,11], ultra-fast microwave method [15], sputtering [4,11] and electrochemical methods [2,3,5,6,14]. Most of the aforementioned strategies required high temperature growth environment [20], costly experimental setups [2,20], long reaction times [2,20] and complicated procedures [2].…”