Critical comparison of light-induced changes in sub-band-gap absorption and photoconductivity in hydrogenated amorphous silicon

Journal Article · Mon Mar 27 00:00:00 EST 1989 · Appl. Phys. Lett.; (United States)

DOI:https://doi.org/10.1063/1.100729· OSTI ID:6418120

Bhattacharya, E; Mahan, A H; Crandall, R S; Pankove, J I

This work compares changes in the density of states due to light-induced degradation estimated by photoconductivity with those measured by photothermal deflection spectroscopy (PDS) on a series of hydrogenated amorphous silicon (a-Si:H) films having different valence bandtail widths (E/sub 0/ ). We find that the photoconductivity measurements indicate orders of magnitude larger defect density changes than do the PDS measurements as the valence bandtail becomes broader. This conflict is resolved by showing that this difference is due to changes in the recombination rate coefficient K with valence bandtail width. The absolute change in K increases exponentially with E/sub 0/. However, the change in K relative to the K of the annealed state decreases with E/sub 0/, explaining why poor material shows a smaller light-induced effect.

• Research Organization: Solar Energy Research Institute, 1617 Cole Boulevard, Golden, Colorado 80401
• OSTI ID: 6418120
• Journal Information: Appl. Phys. Lett.; (United States), Vol. 54:13
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
SILICON
ENERGY-LEVEL DENSITY
PHOTOCONDUCTIVITY
AMORPHOUS STATE
ENERGY GAP
EXPERIMENTAL DATA
HYDROGEN
IMPURITIES
DATA
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
ELEMENTS
INFORMATION
NONMETALS
NUMERICAL DATA
PHYSICAL PROPERTIES
SEMIMETALS
360603* - Materials- Properties