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Title: Determination of defect density of state distribution of amorphous silicon solar cells by temperature derivative capacitance-frequency measurement

In this contribution, we demonstrate the application temperature dependent capacitance-frequency measurements (C-f) to n-i-p hydrogenated amorphous silicon (a-Si:H) solar cells that are forward-biased. By using a forward bias, the C-f measurement can detect the density of defect states in a particular energy range of the interface region. For this contribution, we have carried out this measurement method on n-i-p a-Si:H solar cells of which the intrinsic layer has been exposed to a H{sub 2}-plasma before p-type layer deposition. After this treatment, the open-circuit voltage and fill factor increased significantly, as well as the blue response of the solar cells as is concluded from external quantum efficiency. For single junction, n-i-p a-Si:H solar cells initial efficiency increased from 6.34% to 8.41%. This performance enhancement is believed to be mainly due to a reduction of the defect density in the i-p interface region after the H{sub 2}-plasma treatment. These results are confirmed by the C-f measurements. After H{sub 2}-plasma treatment, the defect density in the intrinsic layer near the i-p interface region is lower and peaks at an energy level deeper in the band gap. These C-f measurements therefore enable us to monitor changes in the defect density in the interface regionmore » as a result of a hydrogen plasma. The lower defect density at the i-p interface as detected by the C-f measurements is supported by dark current-voltage measurements, which indicate a lower carrier recombination rate.« less
Authors:
; ; ;  [1]
  1. Delft University of Technology, PVMD-DIMES, P.O. Box 5053, 2600 GB Delft (Netherlands)
Publication Date:
OSTI Identifier:
22275709
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 115; Journal Issue: 3; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; AMORPHOUS STATE; CAPACITANCE; CHARGE CARRIERS; ELECTRIC CONDUCTIVITY; ENERGY LEVELS; FREQUENCY MEASUREMENT; HYDROGEN; HYDROGENATION; INTERFACES; PLASMA; QUANTUM EFFICIENCY; RECOMBINATION; SEMICONDUCTOR JUNCTIONS; SILICON; SILICON SOLAR CELLS; TEMPERATURE DEPENDENCE