Defect Engineering through Field-Effect-Induced Sensitization of Surface-Confined Grain Coalescence: A Route to Enhanced Electron Mobility in Li-Doped ZnO

In this study, the effect of surface-confined grain coalescence on the electron mobility in ZnO is investigated. Our findings reveal a pronounced increase in electron mobility (7.95 cm2/(V s)) due to the coalescence of ZnO grains on the surface, leading to reduced grain boundary scattering as a result of reduced oxygen and/or zinc vacancies confined to the ZnO surface. A significant decrease in the green emission intensity, typically associated with oxygen vacancies, was observed upon annealing. This reduction suggests a decrease in oxygen vacancies, predominantly located at the grain boundaries, as corroborated by the observed grain growth. Our results emphasize the potential of dopant optimization and postsynthesis treatments through defect engineering in modulating the electronic and optoelectronic properties of ZnO, providing insights that could guide the tailoring of ZnO-based materials for enhanced performance in electronic and optoelectronic applications.