The Carrier Transport Properties of B-Doped Si Nanocrystal Films with Various Doping Concentrations

B-doped hydrogenated amorphous silicon (a-Si:H) films with various doping concentrations were prepared by a plasma-enhanced chemical vapor deposition (PECVD) technique. After thermal annealing, the as-deposited samples, B-doped silicon nanocrystals (Si NCs), were obtained in the films. The electronic properties of B-doped Si NC films with various doping concentrations combined with the microstructural characterization were investigated. A significant improvement of Hall mobility rising to the maximum of 17.8 cm2/V·s was achieved in the Si NC film after B doping, which is due to the reduction of grain boundary (GB) scattering in the B-doped samples. With increasing the doping concentration, it was interesting to find that a metal-insulator transition (MIT) took place in the B-doped Si NC films with high doping concentrations. The different carrier transport properties in the B-doped Si NC films with various doping concentrations were investigated and further discussed with emphasis on the scattering mechanisms in the transport process.