Picosecond Photomodulation Studies of Carrier Trapping in a-Si:H
Subnanosecond trapping in gap states of photogenerated carriers in doped, compensated and undoped a-Si:H, and a—Si:H/a—SiNx:H multilayer structures, was studied by the picosecond pump and probe technique. In undoped a-Si:H the photoexcited carriers are trapped in band-tail states and in compensated a-Si:H in impurities introduced by doping. In singly doped a-Si:H the photoexcited majority carriers are trapped in impurities while the minority carriers are trapped in charged dangling bonds introduced by doping. In a—Si:H/a—SiNx:H superlattices photocarriers are trapped in interface related defects. The transport dynamics of the trapping process is in all cases dispersive.
KeywordsPhosphorus Recombination Boron
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