Tunable Electrical Properties in High-Valent Transition-Metal-Doped ZnO Thin-Film Transistors

High-valent transition-metal (Ti or Mo)-doped ZnO thin-film transistors (TFTs) were fabricated using radiofrequency magnetron sputtering at 150 °C. When the Ti or Mo was doped in the ZnO channel, device characteristics, such as threshold voltage, were modulated and field effect mobility could be enhanced. The device stability of the TFTs with a low Mo content was dramatically improved, which can be attributed to the incorporation of Mo suppressed the generation of oxygen vacancies in the ZnO active channel layer. These results indicate that high-valent transition-metal-doped ZnO TFTs strongly sustain further investigation for their applicability as alternative channel materials.