Fabrication and characterization of novel Ga-doped WO3 films and n-Ga@WO3/p-Si junction diode for optoelectronic device applications

Abstract

In this work, we have fabricated the gallium doped tungsten trioxide (Ga@WO3) films and n-Ga@WO3/p-Si diodes by taking various concentrations (0, 3, 6, 9, and 12 wt%) of Ga through the spin-coating method. To analyze the impact of Ga-dopant on the physical properties of WO3 films, XRD, SEM, and robust dc electrical analyses have been used. From the XRD analysis, compared to the lower concentration of Ga dopant, the higher dopant concentrations show the presence of Ga on the o-GaWO3 crystal structure. The nanoplates-like surface morphology was detected by SEM analysis. The temperature-dependent dc conductivity was studied by I-V characterization, and 12 wt% of Ga doped WO3 thin film exhibits a higher conductivity value and low activation energy (Ea) at room temperature. The J-V nature signifies that n-WO3/p-Si diode performance was enhanced using Ga dopant concentration. The diode constraints ideality factor (n) and barrier height (ΦB) values were determined from J-V, Cheung’s, and Norde's functions. From J-V-T & Richardson plot (ln (J0/T2)), we obtain that the ΦB values were decreased with decreasing temperature. This is explained through the mechanism of thermionic emission with ΦB Gaussian distribution. The determined parameters of the fabricated films and junction diode signify that these can be employed in the applications of photodetectors and solar cells.