ZnO-Based n-Channel Junction Field-Effect Transistor With Room-Temperature-Fabricated Amorphous p-Type $\hbox {ZnCo}_{2}\hbox {O}_{4}$ Gate

ZnO-based junction field-effect transistors were fabricated by pulsed-laser deposition using room-temperature-deposited amorphous p-type ZnCo₂O₄ as heterojunction gate on top of a n-ZnO channel layer. A channel mobility of 8.4 cm²/(Vs), current on/off ratio of 1.3 ×10⁷, and a subthreshold swing of 91 mV/dec were achieved for a transistor with a 40 nm thin channel layer. The devices are normally on and show excellent bias-stress stability, exhibiting a negligible threshold-voltage shift. Elevated temperatures up to 150^°C changed the device performance slightly, but the transistor remains fully operative.