Low Voltage Operating Field Effect Transistors with Composite In2O3-ZnO-ZnGa2O4 Nanofiber Network as Active Channel Layer

Field effect transistors (FETs), incorporating metal-oxide nanofibers as the active conductive channel, have the potential for driving the widespread application of nanowire or nanofiber FETs-based electronics. Here we report on low voltage FETs with integrated electrospun In2O3–ZnO–ZnGa2O4 composite fiber channel layers and high-K dielectric (MgO)0.3-(Bi1.5Zn1.0Nb1.5O7)0.7 gate insulator and compare their performance against FETs utilizing conductive single phase, polycrystalline ZnO or In2O3 channel layers. The polycrystalline In2O3–ZnO–ZnGa2O4 composite fibers provide superior performance with high field effect mobility (∼7.04 cm2V–1s–1), low subthreshold swing (390 mV/dec), and low threshold voltage (1.0 V) combined with excellent saturation, likely resulting from the effective blocking of high current-flow through the In2O3 and ZnO nanocrystallites by the insulating spinel ZnGa2O4 phase. The microstructural evolution of the individual In2O3, ZnO, and ZnGa2O4 phases in composite fibers is clearly obse...