Defects characterization in p-i-n a-Si:H photodiode i-layer

The recombination rate and space charge distribution in the i-layer of a p-i-n a-Si:H photodiode are analyzed using a model with two dangling-bond-correlated energy levels. The effect of various capture cross sections on recombination rate through such dangling bond, DB states has been studied. The dangling bond state energies have been extracted from the transient response of the a-Si:H p-i-n photodiode on concurrent forward voltage and light pulses at low reverse bias voltages. The analysis with respect to the color (energy) of absorbed light is also performed. The results indicate the energy level position corresponding to positive-neutral and neutral-negative transitions close to the p-i and n-i junctions, respectively. This enables further investigation of such defect influence on photodiode transient response with respect to applications in color sensors in an active pixel sensing system. (C) 2012 Elsevier B.V. All rights reserved.