THE MOBILITY-LIFETIME PRODUCT IN DEPLETED A-SI-H DIODES

We have performed transient photoconductivity experiments on well-characterized a-Si:H solar cells which show the following: (A) Under depletion conditions recombination is effectively suppressed, leaving only trapping as a loss mechanism in electron transport. (B) Measured trapping times depend on the experimental time scale. (C) Under non-depleted conditions trapping is dependent on the occupancy of the localized states. Our results clarify the meaning and interpretation of experiments related to time-of-flight work, and explain the observed experimental differences in steady state and transient measurements.