Abstract
GaN has interesting prospects in applications for spectrum-tunable solid-state devices with photoelectric conversion function. Similarly, single nanowires or nanowire arrays (NWAs) proceed to exhibit good photon absorbance and photoemission characteristics as vacuum devices based on the external photoelectric effect. However, the collection of photoelectrons emitted from a nanowire surface has become the greatest impediment to the progress of GaN NWAs photocathodes. In this study, a field-assisted GaN NWA photocathode is proposed. The photoemission efficiency and electron collection efficiency of the field-assisted GaN NWA photocathode are derived. The results suggest that the external field can effectively enhance the photoemission capacity and electron collection efficiency of the photocathode. Based on the theoretical model, the structural parameters of NWAs and the field intensity are optimized. When the field intensity is 1 V μm−1, the collected photocurrent of the GaN NWA photocathode reaches a maximum. For NWAs with an aspect ratio of 1:1, the optimal incident angle of light is 70°. This study provides a theoretical guide for the incorporation of an external field in a GaN NWA photocathode with the purpose of enhancing photoemission and electron collection capacity.
Published Version
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