Synthesis of MO- and W- doped ZnO thin films via the sol-gel technique: Structural, optical, and electrical properties

In this study, molybdenum (2% and 4%) and tungsten (2%) doped zinc oxide (ZnO) thin films were synthesized via the sol–gel spin-coating technique to investigate the effects of high-valence dopants on the structural, vibrational, and electrical behavior of ZnO. The structural properties were examined using X-ray diffraction (XRD), while Fourier-transform infrared spectroscopy (FTIR) was utilized to identify Zn–O bonding characteristics and to evaluate the impact of dopant incorporation on vibrational modes. Spectral analyses were employed to determine the band gap variations, revealing that Mo and W dopants induced notable changes in lattice strain and electronic transitions. Electrical characterization using current–voltage (I–V) measurements showed that dopant concentration significantly affects carrier transport, ideality factor, and Schottky barrier parameters. Moreover, the quality of the diode structure was assessed based on the calculated ideality factors, providing insight into interfacial properties and transport mechanisms. Overall, the findings demonstrate that sol–gel-derived Mo- and W-doped ZnO thin films exhibit enhanced properties suitable for transparent electronics, diode applications, and advanced sensing technologies.