Field emission properties of amorphous GaN ultrathin films fabricated by pulsed laser deposition

Amorphous gallium nitride (a-GaN) films with thicknesses of 5 and 300 nm are deposited on n-Si (100) substrates by pulsed laser deposition (PLD), and their field emission (FE) properties are studied. It shows that compared with thicker (300 nm) a-GaN film, better FE performance is obtained on ultrathin (5 nm) a-GaN film with a threshold field of 0.78 V/µm, which is the lowest value ever reported. Furthermore, the current density reaches 42 mA/cm2 when the applied field is 3.72 V/µm. These experimental results unambiguously confirm Binh’s theoretical analysis (Binh et al. Phys Rev Lett, 2000, 85(4): 864–867) that the FE performance would be prominently enhanced with the coating of an ultra-thin wide band-gap semiconductor film.