Electron spin resonance in doped nanocrystalline silicon films

We report studies of electron spin resonance (ESR) and its related defect states in doped nanocrystalline silicon films (nc-Si:H). The samples used, which were prepared by the plasma enhanced CVD method, contain two phases, i.e. nanocrystallites embedded in an amorphous matrix. For phosphorus doped nc-Si:H samples, the measured ESR g-values are 1.9990-1.9991, the line width DeltaH(pp) 40-42 G, and the ESR density N-ss is of order of 10(17) cm(-3). For boron doped nc-Si:H samples, the measured ESR g-values are 2.0076-2.0078, the DeltaH(pp) is about 18 G, and the N-ss is of order of 10(17) cm(-3). Considering the microstructural and conducting characteristics of these kinds of films, we discuss and give explanations to the ESR sources, their DeltaH(pp) and N-ss as well. We intend to ascribe the ESR signal in phosphorus doped nc-Si:H to the unpaired electrons in the high density defect states located in the interfaces of nanocrystallites/amorphous matrix, and that in boron doped ones to the unpaired electrons in the valence band-tail states in the a-Si:H tissue of their amorphous matrix. (C) 2001 Elsevier Science Ltd. All rights reserved.