Electronic behaviour and field emission of metal–semiconductor–insulator–metal (MSIM) heterostructures based on a-C:H films

In this paper, we report on electronic and field emission properties of metal–semiconductor–insulator–metal (MSIM) heterostructures employing semiconducting and insulating hydrogenated amorphous carbon (a-C:H) films. The a-C:H layers were deposited from plasma polymerisation of methane in a 20 kHz discharge. The current as a function of voltage (I–V) characteristic is consistent with Fowler–Nordheim (F–N) type tunnelling of carriers from semiconductor cathode into polymer-like a-C:H. The onset field for emission is about ∼6 V/μm. The transition barrier is found to be ∼0.05 eV, which is close to that obtained with a-C:H:N/Si heterojunctions. capacitance–voltage (C–V) measurements show negligible hysteresis and zero flat band voltage, and the interface states density, estimated from capacitance–frequency plot, is very low (NSS∼4×1010 cm−2). Heterostructures based on amorphous carbon films are perspective for the development of field emission displays (FEDs).