Monolithically integrated GaN nanoscale air channel field emission diode and transistor*

GaN has many superior properties for nanoscale field emission devices, including low electron affinity (χ), high thermal and chemical stability, and high break down field. In particular, the significantly lower electron affinity of GaN compared to typical emitter materials (Si, Mo, W) can potentially enable dramatic improvement of field emission current. Here, we demonstrate monolithically fabricated GaN nanoscale vacuum electron diodes and transistors with ultra-low voltage operation (diode turn on (V_on) ~ 0.24 V) in air. Some notable findings are: 1) the vacuum diodes exhibit nearly linear dependence of V_on with nanogap size (d), and 2) the emission current shows complex pressure dependency even for d < electron mean free path. The field emission transistors are fabricated on single, bi-, and tri-gate configurations, where tri-gate allows independent control of vacuum barrier & GaN work function. We will present results for the design and characteristics of field emission diodes and transistor at various nanogap sizes and operating pressures.