Charging and Coulomb blockade effects of the nc-Si embedded in SiNx double-barrier structures

We fabricated a series of a-SiNx/nc-Si/a-SiNx double-barrier structures by plasma-enhanced chemical vapor deposition and subsequent thermal annealing technique. The photographs of transmission electron microscopy show that the nc-Si layer has been formed. The estimated density of nc-Si dots is of the order of 1011–1012 cm−2. In the C–V measurements, for the samples with thicker SiNx layer (30 nm), we observed C–V hysteresis characteristics, which can be explained by charging effect in nc-Si through the F–N tunneling mechanism; while for the sample with thinner SiNx layer (5 nm), the C–V curves show the peak structures which can be attributed to the resonant tunneling of electrons into nc-Si controlled by Coulomb blockade effect. From the interval bias voltage between the two peaks, the Coulomb charging energy of nc-Si dot was estimated.