Process-Dependent enhancement of piezoelectric performance in Ga-Doped ZnO thin films for energy harvesting applications

This study explores the enhancement of piezoelectric properties in zinc oxide (ZnO)-based thin films through gallium (Ga) ion doping using various fabrication processes. Three distinct doping methods and two doping concentrations (1% and 3%) were systematically investigated. Experimental results reveal that Ga-doped ZnO (GZO) films exhibit reduced electrical resistivity, increased optical transmittance, and wider bandgaps compared to undoped ZnO films. Among the examined conditions, GZO films with 1% Ga 3⁺ doping achieved the lowest resistivity of 0.0065 Ω·cm and the highest piezoelectric output of 1098.83 mW. In contrast, excessive Ga 3 ⁺ doping at 3% led to increased lattice defects, inducing internal stress and electric field screening effects that diminished the piezoelectric performance. Durability assessments further confirmed the mechanical robustness and long-term stability of GZO devices under sustained vibrational loading. These findings underscore the effectiveness of Ga³⁺ doping in enhancing the piezoelectric performance of ZnO thin films and highlight their potential for applications in energy harvesting technologies.