Electronic characteristics of n-type nanocrystalline/p-type crystalline silicon heterostructure

A heterojunction of ultrathin phosphorus-doped hydrogenated nanocrystalline silicon with p-type crystalline silicon was fabricated to investigate carrier information and conduction behaviour. The temperature-dependent carrier information of holes and electrons as well as the two-dimensional electron gas were identified. The forward conduction can be ascribed to tunnelling-aided carrier emission recombination while the reverse transport can be divided into different mechanisms within different reverse bias ranges. The reverse current can be assigned to minority carrier tunnelling through the space charge region within the backward bias voltage from 0 to about - 10 V. With decreasing negative applied voltage from - 10 V to around - 22 V, the reverse current can be attributed to the tunnelling-assisted Poole - Frenkel emission. With further reduction of the reverse bias voltage from - 22 V to about - 38 V under 100 K, the reverse current staircases can be allocated to sequential resonant tunnelling; otherwise it can be due to the thermic effect at higher temperature. The main origin of short transient time for the fabricated device can be due to the tunnelling mechanism.