Enhanced electrical properties and stability of GaZnSnO TFTs: the role of gallium composition

Abstract This study investigates the influence of gallium (Ga) doping concentration on the electrical properties and stability of amorphous GaZnSnO (a-GZTO) thin-film transistors (TFTs). a-GZTO TFTs with 1 wt% and 2 wt% Ga content were fabricated via RF magnetron sputtering at room temperature and evaluated for their performance. The 1 wt% Ga-doped a-GZTO TFT exhibited a high field-effect mobility of 25.8 cm 2 /V·s, indicating excellent charge transport characteristics. Both devices showed good thermal stability under temperature stress, with the 2 wt% device exhibiting a smaller threshold voltage shift (Δ V TH ). Density of states (DOS) analysis revealed subtle differences in defect characteristics between the two doping levels. Increasing Ga content from 1 wt% to 2 wt% led to a reduction in mobility (from 25.8 to 21.2 cm 2 /V·s), accompanied by a decrease in oxygen vacancy concentration, as confirmed by x-ray photoelectron spectroscopy (XPS). These results demonstrate that Ga doping concentration in a-GZTO TFTs can be effectively tuned to achieve a trade-off between high mobility and enhanced device stability, making them promising candidates for next-generation display applications.