Electronic transport in silicon quantum dots (Si-QDs) in core/shell configuration was studied. The nC-Si cores encapsulated by protective SiOx shells embedded in a-Si matrix were obtained from one-step and spontaneous plasma processing, at low substrate temperature (300 degrees C) compatible for device fabrication. The size, density and distribution of nC-Si QDs were controlled by optimizing the plasma parameters. Very high electrical conductivity, sigma similar to 4 x 10(-2) S cm(-1), was achieved at a total number density of Si-QDs, N similar to 4.8 x 10(11) cm(-2), corresponding to the lowering in its average core size, d similar to 3.7 nm, to the order of the bulk Si exciton Bohr radius and the associated quantum confinement effects. The electrical conductivity was demonstrated to exhibit quantum size (3 < d (nm) < 10) effect in zero dimensional quantum dots. The underlying electronic transport was explained using heteroquantum-dot model, the nC-SiOx:H QDs possess hetero-junction like band structure in the interface regions, due to their different band gaps. (c) 2012 Elsevier Ltd. All rights reserved.