Field Emission Enhancement in Semiconductor Nanofilms by Engineering the Layer Thickness: First-Principles Calculations

Abstract

We investigated the field emission (FE) enhancement of semiconductor thin films on metal substrate by first-principles calculations. For the FE structure of GaN or AlN thin films on aluminum substrate, the calculated results show that by fine-tuning the film thickness, the FE current can be enhanced nearly 2 orders. It should be originated from reducing the surface work function. When the film thickness is less than ∼10 nm, the work function can be reduced as much as 0.5 eV by film thickness modulation of only several nanometers. The remarkable thickness effects on the work function for the semiconductor/metal structure result mainly from surface/interface charge transfer and interface states.