A comparison of the hydrogenated amorphous Si schottky barrier and the hydrogenated amorphous Si p—i—n dark forward-bias current density—Voltage characteristics

Abstract

Abstract Using detailed computer simulations we explore the origin of the current density differences experimentally observed in the dark current density—voltage (J—V) characteristics of hydrogenated amorphous Si (a-Si:H) Schottky barriers and a-Si:H p—i—n homojunctions. Schottky barrier devices show higher dark current densities at low forward biases and p—i—n devices show higher current densities at high forward biases. Computer modelling shows that at low forward voltages the transport mechanism limiting the total current density is drift diffusion over the barrier in Schottky barriers and recombination through localized states in p—i—n diodes. On the other hand at high forward bias voltages the limiting transport mechanism is electron space-charge-limited current in both devices. We found that the non-blocking nature of the p—i—n front contact is the ultimate cause for the higher current densities observed experimentally in a-Si:H p—i—n structures at high forward biases. In this paper we also compare ...