Effect of Zinc Oxide Doping on the Structural and Optical Characterization of Nanostructured Molybdenum Oxide Films

Abstract

Undoped and zinc oxide (ZnO) doped molybdenum oxide (MoO3) films were prepared by RF magnetron sputtering technique. The influence of doping and post annealing temperature on the structural and optical properties of these films were investigated systematically using X-ray diffraction (XRD), energy dispersive X-ray analysis (EDAX), scanning electron microscopy (SEM), atomic force microscopy (AFM), UV-VIS spectroscopy and photoluminescence spectroscopy (PL). The XRD patterns indicate the presence of stoichiometric orthorhombic alpha-MoO3 phase in the annealed (573 and 673 K) undoped molybdenum oxide films and in ZnO doped molybdenum oxide film (annealed at 673 K). The crystalline grain size in the films was investigated using Debye Scherrer formula and corrected using Hall-Williamson equation. The SEM and AFM images revealed the distribution of nano leafs, nanorods and nanograins. Nanorods of length 1.4 microm and diameter 149 nm can be observed in ZnO doped films. The optical band gap energy was found to increase with increase in annealing temperature and particle size. These nanostructures show a room temperature PL emission in the UV and visible region.

Photoluminescence in laser ablated nanostructured indium oxide thin films

“…But in the case of annealed A films the variation of values of band gap energy is not in accordance with particle size variation. Srikant and Clark [28], Dutta et al [29] and Navas et al [30] have reported similar observation of decrease in band gap energy with decrease in particle size. In nanocrystalline materials the surface to volume ratio is higher and band bending can be expected at the grain boundaries.…”

“…In bigger grains the band edge becomes sharp and band gap can be wider than that of smaller grains. Hence the observed decrease in band gap energy with decrease in particle size can be attributed to band bending effect at the particle boundaries [28][29][30] as the grain size decreases at higher annealing temperature of 773 and 973 K.…”

Alteration of architecture of MoO3 nanostructures on arbitrary substrates: growth kinetics, spectroscopic and gas sensing properties

“…[17][18][19][20][21][22] RF magnetron sputtering under an excessive argon atmosphere and subsequent controlled calcination in atmospheric air was recognized as an efficient method for the preparation of MoO 3 nanostructures on glass substrates by our previous studies. [37][38][39] The fabrication of MoO 3 nanostructures in thin film form on a substrate base is highly influenced by the deposition method, nature of the substrates, deposition temperature, growth time, deposition pressure, vacuum quality, calcination temperature, etc. A crucial challenge in this field is the proper choice of the substrate as the nature of the substrate can alter the morphology and spectroscopic properties of the nanostructures owing to thermal mismatch (owing to the difference in thermal expansion coefficients) and lattice mismatch between the substrates and MoO 3 .…”

Thermal and Optical Properties of In and In2O3 Nanoparticles Synthesized Using Pulsed Plasma in Water

“…Because of the quantum confinement effect, the band gap energy increases with decreasing crystallite size . The increase or decrease of the band gap energy of In 2 O 3 thin films or nanostructures have been discussed in literature . The band gap energy of In 2 O 3 nanomaterials (particles and thin films) obtained by different methods are listed in Table ; it is evident that our In 2 O 3 NPs were the smallest in size among the reported nanomaterials, whereas the band gap energy was comparable.…”

“…[42][43] The increase or decrease of the band gap energy of In 2 O 3 thin films or nanostructures have been discussed in literature. [44][45][46] The band gap energy of In 2 O 3 nanomaterials (particles and thin films) obtained by different methods [47][48][49][50][51] are listed in Table 1; it is evident that our In 2 O 3 NPs were the smallest in size among the reported nanomaterials, whereas the band gap energy was comparable. The small size, excellent structural/thermal properties, and high band gap energy of In and In 2 O 3 NPs demonstrate that our NPs can be good [47] In 2 O 3 NPs 15-30 3.45 Sono chemical [48] In 2 O 3 NPs 43 3.4 Plasma assisted hot wire CVD [49] In 2 O 3 TF b) 40…”