Structure-Stress Engineering for Controllable Integration of ZnO Nanowires in Gated Field Emitter Arrays

Abstract

Gated field-emission arrays (FEAs) based on nanowires have significant applications in vacuum microelectronic devices. Controllable integration of nanowires in microstructures is a key issue to be solved in gated FEAs. Structural design is a general strategy for stress redistribution to regulate nanowire growth. As a model system, we identify microstructure-induced stress variation as a critical factor that governs nanowire growth and emission uniformity in gated ZnO nanowire FEAs. To overcome this problem, we propose an inner-gate structure to eliminate the stress release caused by vias for optimizing the growth of ZnO nanowires. The maximum emission current density (5.53 mA/cm2) and transconductance (2606 nS) obtained in this work are higher than those of the previously reported gated ZnO nanowire FEAs. Moreover, an anode probe is employed to measure the field-emission characteristics from a single pixel of inner-gate ZnO nanowire FEAs. The self-limiting current effect of ZnO nanowires is found to improve the pixel uniformity of the device. The addressing characteristics of the fabricated ZnO nanowire FEAs have been studied for flat-panel display applications. This work demonstrates that structure-stress engineering provides a general method for optimizing nanomaterial growth in microstructures.