Low-voltage ZnO thin-film transistors with high-KBi1.5Zn1.0Nb1.5O7 gate insulator for transparent and flexible electronics

We report on the fabrication of field-effect transistors with transparent oxide semiconductor ZnO serving as the electron channel and high-KBi1.5Zn1.0Nb1.5O7 (BZN) as the gate insulator. The devices exhibited very low operation voltages (<4V) due to high capacitance of the BZN dielectric. The field effect mobility and the current on/off ratio were 0.024cm2∕Vs and 2×104, respectively, at an operating voltage of 4 V. The threshold voltage and subthreshold swing were 2 V and 0.25V∕dec, respectively. The high optical transparency (>80% for wavelength >400nm), low-temperature processing, and low operation voltage of ZnO-based thin-film transistors with integrated BZN dielectric offer a promising route for the development of transparent and flexible electronics.