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Proceedings Paper

Picosecond Photomodulation Spectroscopy In Amorphous Semiconductors
Author(s): Z. Vardeny; C. Thomsen; H. T. Grahn; J. Tauc
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Paper Abstract

Picosecond trapping of photogenerated carriers in gap states of doped, compensated and undoped amorphous hydrogenated silicon (a-Si:H) and of a-Si:H based superlattices was studied by the pump and probe photomodulation technique. In undoped a-Si:H the photogenerated carriers are trapped in bandtail states and in compensated a-Si:H in impurity states introduced by doping. In singly doped a-Si:H the photoexcited majority carriers are trapped in impurity states whereas the photoexcited minority carriers are trapped in charged dangling bond defects. In a-Si:H/a-SiNx:H superlattices photocarriers are trapped in interface related defects. In all cases we found that electron trapping is about 50 times faster than hole trapping. This intrinsic property of a-Si:H originates from a larger electron hopping rate among localized states in the conduction band-tail.

Paper Details

Date Published: 3 August 1987
PDF: 8 pages
Proc. SPIE 0793, Ultrafast Laser Probe Phenomena in Bulk and Microstructure Semiconductors, (3 August 1987); doi: 10.1117/12.940878
Show Author Affiliations
Z. Vardeny, Brown University (United States)
C. Thomsen, Brown University (United States)
H. T. Grahn, Brown University (United States)
J. Tauc, Brown University (United States)


Published in SPIE Proceedings Vol. 0793:
Ultrafast Laser Probe Phenomena in Bulk and Microstructure Semiconductors
Robert R. Alfano, Editor(s)

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