Influence of nanocrystal size on the transport properties of Si nanocrystals

Abstract

In this study, we have investigated the carrier transport mechanism across silicon nanocrystals with the Al/p-Si/Si nanocrystals/Al structure. Sizes of silicon nanocrystals were controlled at diameters of ∼6, ∼8, and ∼11 nm. It is shown that the conductivity σ of silicon nanocrystals, both as-grown and annealed, exhibits σ∝exp[−(T0/T)]1/2 behavior under low electrical fields and over a wide temperature range. The phenomenon of material constant T0 increasing with the decrease of nanocrystal size has been observed. Considering nanocrystal size effect, experimental results can be explained by the hopping-percolation model. The influence of nanocrystal size on transport properties has been discussed. Based on this model, changes in T0 after annealing treatment are attributed to an increase in effective decay length.