Ultralow Voltage GaN Vacuum Nanodiodes in Air

• Published in: Nano letters Vol. 21; no. 5; pp. 1928 - 1934
• Main Authors: Sapkota, Keshab R, Leonard, François, Talin, A. Alec, Gunning, Brendan P, Kazanowska, Barbara A, Jones, Kevin S, Wang, George T
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 10.03.2021
• Subjects: field emission; field enhancement; GaN; nanogap; NANOSCIENCE AND NANOTECHNOLOGY; vacuum electron; field enhancement; GaN; field emission; vacuum electron; nanogap
• ISSN: 1530-6984; 1530-6992
• DOI: 10.1021/acs.nanolett.0c03959

The III-nitride semiconductors have many attractive properties for field-emission vacuum electronics, including high thermal and chemical stability, low electron affinity, and high breakdown fields. Here, we report top-down fabricated gallium nitride (GaN)-based nanoscale vacuum electron diodes operable in air, with record ultralow turn-on voltages down to ∼0.24 V and stable high field-emission currents, tested up to several microamps for single-emitter devices. We leverage a scalable, top-down GaN nanofabrication method leading to damage-free and smooth surfaces. Gap-dependent and pressure-dependent studies provide new insights into the design of future, integrated nanogap vacuum electron devices. The results show promise for a new class of high-performance and robust, on-chip, III-nitride-based vacuum nanoelectronics operable in air or reduced vacuum.