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 ϳ6, ϳ8, and ϳ11 nm. It is shown that the conductivity of silicon nanocrystals, both as-grown and annealed, exhibits ϰ exp͓−͑T 0 / T͔͒ 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.

Ultrafast percolative transport dynamics in silicon nanocrystal films

“…In order to identify possible causes of the time variation of the Drude-Smith c parameter, and the corresponding time-varying average probability of carrier reflection at the nanocrystal boundaries, mechanisms of internanocrystal carrier transport need to be considered. Various conduction models, such as thermionic emission, 6,7 tunneling across nanocrystal boundaries, and variable-range hopping, 7,8 have been suggested to explain long-range conduction in networks of connected silicon nanocrystals embedded in SiO 2 . Regardless of the specific conduction mechanism at work, as the carriers move in the multinanocrystal pathways, they encounter surface and interface defects that act as highly efficient trap states.…”

Influences of defects and Sb valence states on the temperature dependent conductivity of Sb doped SnO 2 thin films

“…Grain boundaries are known to play a critical role in carrier mobility which would significantly influence the electrical resistance of thin films [13]. Semiconductors with small nanocrystal size usually show a strong temperature dependent conductivity [25]. In fact, the variations in grain boundary and nanocrystal size are usually accompanied by evolution of defects in ATO films, which can be probed by DBAR.…”

Size effects on hopping conduction in Si nanocrystals

“…The value of s max for the present samples is independent of the nanocrystal size and can roughly be estimated to be ~3nm. To make a quantitative comparison with experimental results, we use the Si nanocrystal diameter for the individual samples and assume and P C as 0.1nm and 0.25 [7] to calculate T 0 based on Eq.2. The calculation results agree with the experimental results very well, as shown in Tab.1.…”