Influence of nanocrystal size on the transport properties of Si nanocrystals

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 similar to 6, similar to 8, and similar to 11 nm. It is shown that the conductivity sigma of silicon nanocrystals, both as-grown and annealed, exhibits sigma alpha exp[-(T(0)/T)](1/2) behavior under low electrical fields and over a wide temperature range. The phenomenon of material constant T(0) 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 T(0) after annealing treatment are attributed to an increase in effective decay length. (C) 2008 American Institute of Physics.