Kilo-Voltage Thin-Film Transistors for Driving Nanowire Field Emitters

High-voltage thin-film transistors (HV-TFTs) based on amorphous InGaZnO (a-IGZO) are demonstrated to work in the range of kilo-voltage (kV). The devices feature a high breakdown voltage of over 1.1 kV, on-current of 10.8 $\mu \text{A}$ , and an on/off current ratio over 10(5). By integrating kV-TFTs with ZnO nanowires, actively controlled field emitters are obtained that exhibit extremely small current fluctuation in the emission current (2.4 % for 3600s). The operating mechanisms of the HV-TFTs are investigated by in-situ measurement of channel potentials and simple equations are derived to describe the current-voltage relations. This study demonstrates the feasibility of using a-IGZO in HV-TFTs that drive large-area field-emitter arrays and provide general understanding and design rules for HV-TFTs designed to drive nanowire field emitters.