Hierarchical porous Ga doped ZnO films synthesized by sol-electrophoretic deposition

Abstract

In this study, Ga-doped zinc oxide (GZO) branched nanoparticles are synthesized by sol-electrophoretic deposition to investigate structural, morphological, size distribution, and optical properties evolution induced by Ga content. By selecting the optimum conditions in electrophoretic deposition (voltage = 10 V and time = 10 min) that provide the most uniform morphology, undoped zinc oxide (UZO) sample with hierarchical shape is obtained. For finding the optimum GZO sample for higher crystallinity and surface uniformity, different concentrations of Ga dopant are added to the system in predetermined voltage and time. Impurities increase the crystal energy and cause sizeable structure variation in formation of nanoparticles. This phenomenon causes Ga-doped samples in proper concentration have more fine particles rather than UZO. Ga dopant in a concentration of 1 mol% of Ga/Ga+Zn shows the most proper morphological and structural results. At this concentration, XRD peaks elucidate the highest crystallinity and a peak shift to higher angle due to appropriate Ga doping. HRXPS results show the efficient doping process at this chosen concentration of Ga. DRS spectra demonstrate a higher light trapping in the concentration of 1 mol% of Ga in comparison to UZO. Resistivity diagram shows Ga in concentration of 1 mol% have highest conductivity.