Dependence of electrical and optical properties of sol–gel prepared undoped cadmium oxide thin films on annealing temperature

The importance of the methanol content in the precursor solution, on the physical properties of cadmium oxide thin films prepared by the sol–gel method

“…The undoped and fluorine doped CdO precursor solutions were prepared following the procedure previously reported by the authors [16,17]. For the undoped CdO precursor solution, four methanol contents were used: 33, 37, 41 and 46 mol, with respect to 1 mol of cadmium acetate.…”

“…Different types of simple heterojunction solar cells have been studied: CdO/crystalline-Si [1], CdO/CdTe [2][3][4][5], CdO/Cu 2 O [6], CdO/CuGaInSe [7] and CdO/ITO in dye-sensitized solar cells, where the CdO has been employed in place of TiO 2 [8]. As well, CdO films can be obtained by several techniques, such as, reactive sputtering [9][10][11], activated reactive evaporation [3,12], chemical bath deposition [13], spray pyrolysis [14], rapid thermal oxidation [1], sol-gel [15][16][17][18] and recently In, Sn, Al and Ti doped CdO films deposited by pulsed laser technique [19][20][21][22]. In order to diminish the cost of the solar cells, it is important to use simple and cheaper deposition techniques.…”

UV irradiation influence on the structural and optical properties of CdO thin films

“…No significant variation of the bandgap value has been found. From the literature data, the direct band-gap values for CdO films prepared by different techniques ranged between 2.2 and 2.8 eV [26,27,28,30,31,33,34]. Similar values of E g (2.20-2.29 eV) were found for CdO films prepared by spray pyrolysis [32,34] and magnetron sputtering [29].…”

Optical Characterization of (CdO)x(ZnO)1-xComposite by Spray Pyrolysis Technique

“…• C [37].) By approaching the lower resistance, eh excitons are able to reach (within its life time) the interface among (CdO) grains and recombine radiatively, a comparable trend could describe sample with value of x = 0.…”

“…The presence of conductive (ZnO) cluster embodied in higher resistance (CdO) matrix will enhance the recombination of eh excitons in the (ZnO) clusters. On these bases the increase of luminescence yield could be attributed to the high resistivity of cadmium oxides, that has high resistivity values of 2 to 20 × 10 −4 Ω cm −1 for those lms deposited by dierent techniques such as reactive sputtering [35] and chemical vapor deposition [36], whereas for simpler techniques such as spray pyrolysis, resistivity values are reported to be between 10 −3 and 10 −2 Ω cm −1 [37]. To enable direct comparison between the luminescence spectra measured for dierent samples at dierent annealing temperatures, the integrated luminescence yields are calculated and presented in bar plot, Fig.…”