Deposition Rate-Controlled Functional Evolution of p-Type Selenium-Alloyed Tellurium-Tellurium Oxide Films for Thin-Film Transistors.

The development of p-type amorphous oxide semiconductors (AOSs) has long been a major challenge that limits the advancement of oxide electronics. Selenium-alloyed tellurium-tellurium oxide (SeTe-TeOx) has emerged as a promising p-type AOS with electrical properties and stability comparable to n-type counterparts. However, the influence of deposition kinetics on the functional properties remains unexplored. Here, the thermal deposition rate is systematically controlled to investigate its impact on the chemical structure, microstructure, and optoelectronic properties of SeTe-TeOx films. Thermodynamic studies and experimental analyses reveal that increasing the deposition rate promotes the formation of Te-Te metallic bonds within the oxide matrix, enabling effective modulation of electrical properties while maintaining a near-amorphous structure. Thin-film transistors exhibit an enhancement in average field-effect mobility from 8.2 to 20.0 cm2 V-1 s-1 along with improved bias stability. This tunability reflects a transition from percolation-limited to well-percolated transport with increasing deposition rate. Complementary analyses further reveal that the well-connected transport network suppresses the macroscopic influence of kinetically slow trapping, despite a greater contribution from interfacial and near-band-edge states. These findings provide fundamental insights into the process-property linkages in SeTe-TeOx and establish deposition rate as a simple yet powerful strategy for engineering p-type oxide electronics.