Conduction behaviour of hydrogenated nanocrystalline silicon backward diode

摘要

A heavy phosphorus doped hydrogenated nanocrystalline silicon ((n~+)nc-Si:H) film was deposited by plasma enhanced chemical vapour deposition technique on a heavy doped p-type crystal silicon substrate to form a heterojunction of (n~+)nc-Si:H/(p~+)c-Si. From electrical measurements of this prepared structure, both negative resistance in forward current-voltage (I-V) measured plots and large reverse current in reverse I-V experimental curves were observed, which reveal the structure as a semiconductor backward diode. The forward current can be assigned to interband tunnel, excess, hump and thermionic emission component, while the reverse current which shows exponential dependence on applied voltage can be ascribed to an internal field emission (Zener mechanism) term. Also, the crucial role of (n~+)nc-Si:H in I-V characteristics was analyzed.