Evaluation of microstructural and electrical properties of WO3-x thin films for p-Si/n-WO3-x/Ag junction diodes.

The ln(J)-V-T characteristics of the p-Si/n-WO 3-x /Ag junction diode have been analyzed by thermionic emission (TE) mechanism with Gaussian distribution (GD) of the barrier heights. The ultra-fine homologous phases of tungsten oxide (WO 3-x ) thin films on the glass substrate can be prepared simply via sol-gel spin coating method. The oxygen reduction of the tungsten trioxide (WO 3 ) thin films was experimentally controlled by various organic acid additives. The organic acid-treated films have hexagonal and monoclinic crystallographic Magneli phases of W n O 3n-2 series (WO 2.92 , WO 2.9 and WO 2.89 ). The morphological changes in the plate-like structure under the strong influence of the organic acids were observed from SEM analysis. In the temperature dependent dc electrical conductivity, the charge transport mechanism of the WO 3-x thin films was analyzed by Arrhenius, Mott’s variable hopping, small polaron mechanisms. From the J-V-T characteristics of the p-Si/n-WO 3-x /Ag diode, the increasing of barrier height (Φ B ) and decreasing of ideality factor (n) reveal that barrier inhomogeneities at the interface, which is assumed by Gaussian distribution. The mean barrier height ( Φ B ) , the standard deviation (σ 0 2 ) and Richardson constant (A*) values were investigated in the temperature range 303−423 K. The better diode performance was acquired to the Si/WO 2.89 /Ag device with the experimentally intended A* value of 34.81 A/cm 2 /K 2 which is near to the well-known value of 32 A/cm 2 /K 2 for p-type Si. [ABSTRACT FROM AUTHOR]