Growth, structural, electrical and optical properties of the thermally evaporated tungsten trioxide (WO3) thin films

Optical band gap and Raman spectra in some (Bi2O3)x(WO3)y(TeO2)100−x−y and (PbO)x(WO3)y(TeO2)100−x−y glasses

“…In some (Bi 2 O 3 ) x (WO 3 ) y (TeO 2 ) 100ÀxÀy glasses the non-linear refractive index was found: n 2 % 4.9 Â 10 À12 esu (x = 10, y = 30) and n 2 % 7.8 Â 10 À12 esu (x = 10, y = 20) and the optical band gap (E g (x, y)) was found: E g (10, 30) = 2.47 eV and E g (10, 20) = 2.7 eV [10]. Optical band gap of amorphous TeO 2 , Bi 2 O 3 and WO 3 was found to be: E g (TeO 2 ) = 3.3-3.7 eV [16,17]; E g (Bi 2 O 3 ) = 2.4-2.8 eV [18,19] and E g (WO 3 ) % 3.38 eV [20], respectively. Using 'alloy like approach' [21], the optical band gap of (Bi 2 O 3 ) x (WO 3 ) y (TeO 2 ) 100ÀxÀy glasses can be estimated using the following relation: 3 ) + (100ÀxÀy) E g (TeO 2 )]/100 and, hence, for instance: 3.23 eV 6 E g,calc.…”

Microstructural evolution of tungsten oxide thin films

“…Conventionally WO 3 films are prepared by sol gel [16], pulsed laser deposition [17], thermal evaporation [18], electron beam evaporation [19], and sputtering [20]. However, the advantage of reactive magnetron sputtering for this purpose is mainly due to the high deposition rate by sputtering from metallic target, which also enables control of the stoichiometry of the deposited films.…”

Effect of W–Ti target composition on the surface chemistry and electronic structure of WO3–TiO2 films made by reactive sputtering

“…This observation can be explained through an understanding of both the heat of formation of the Ti and W oxides, as well as their respective atomic sputtering kinetics [34]. The heats of formation reported for WO 3 and TiO 2 are -840 kJ/mol and -944 -kJ/mol, respectively [35,36].…”

“…Tungsten oxide (WO 3 ) is a widely studied "chromogenic" material with interesting structural, electronic and optical properties for utilization in many scientific and technological applications [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15]. Among metal oxide semiconductors, WO 3 has become a focal point of interest where nanostructured and low-dimensional forms of WO 3 are beneficial for technological development.…”

“…WO 3 thin films and nanostructures exhibit an optical band gap (~2.4-3.2 eV, depending on processing conditions) that permits efficient use of the solar spectrum including absorption in the blue part of the visible region and the ultraviolet region, as well as a high transmission region that extends from the near-infrared (IR) to the visible spectrum [1][2][3][4]. Coupled with good electronic transport properties, photosensitivity, and chemical integrity, WO 3 -based materials are attractive for applications related to sustainable energy production including energy efficient windows and architecture, photoelectrochemical water-splitting, photocatalysis and solar cells [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16]. While WO 3 photo-catalysts find many interesting industrial applications, their photocatalytic and electronic properties are highly influenced by the structure and composition [16].…”