Effects of Ambience on Thermal-Diffusion Type Ga-doping Process for ZnO Nanoparticles

Various annealing atmospheres were employed during our unique thermal-diffusion type Ga-doping process to investigate the surface, structural, optical, and electrical properties of Ga-doped zinc oxide (ZnO) nanoparticle (NP) layers. ZnO NPs were synthesized using an arc-discharge-mediated gas evaporation method, followed by Ga-doping under open-air, N-2, O-2, wet, and dry air atmospheric conditions at 800 degrees C to obtain the low resistive spray-coated NP layers. The I-V results revealed that the Ga-doped ZnO NP layer successfully reduced the sheet resistance in the open air (8.0 x 10(2) omega/sq) and wet air atmosphere (8.8 x 10(2) omega/sq) compared with un-doped ZnO (4.6 x 10(6) omega/sq). Humidity plays a key role in the successful improvement of sheet resistance during Ga-doping. X-ray diffraction patterns demonstrated hexagonal wurtzite structures with increased crystallite sizes of 103 nm and 88 nm after doping in open air and wet air atmospheres, respectively. The red-shift of UV intensity indicates successful Ga-doping, and the atmospheric effects were confirmed through the analysis of the defect spectrum. Improved electrical conductivity was also confirmed using the thin-film-transistor-based structure. The current controllability by applying the gate electric-field was also confirmed, indicating the possibility of transistor channel application using the obtained ZnO NP layers.

Automated summary

This study investigates the properties of Ga-doped zinc oxide nanoparticle layers under various annealing atmospheres. The results show that Ga-doping successfully improves the electrical properties of the nanoparticle layers, and the atmospheric effects are confirmed through defect spectrum analysis.