Influence of relaxation processes on the evaluation of the metastable defect density in Cu(In,Ga)Se{sub 2}
- Faculty of Physics, Warsaw University of Technology, Koszykowa 75, Warszawa 00 662 (Poland)
In this contribution, we investigated by means of numerical simulations the influence of relaxation processes related to metastable defects on electrical characteristics of Cu(In,Ga)Se{sub 2}. In particular, we analyzed the relaxation of a metastable state induced by illumination at a fixed temperature as well as the dependence of the hole concentration on the temperature during cooling. The knowledge of these two relaxation processes is crucial in the evaluation of the hole concentration in the relaxed state and after light soaking. We have shown that the distribution of the metastable defects can be considered frozen below 200 K. The hole capture cross section was estimated as ∼3 × 10{sup −15} cm{sup 2}. It was shown that the usually used cooling rates may lead to relevant changes of the hole concentration. We calculated the lower limit of the hole concentration after cooling, and we presented how it depends on densities of shallow acceptors and metastable defects. Moreover, we proposed a method which allows for the evaluation of shallow acceptor and metastable defect densities from two capacitance-voltage profiles measured in the relaxed and light soaking states. Finally, we indicated experimental conditions in which the influence of relaxation processes on the accuracy of this method is the smallest.
- OSTI ID:
- 22596763
- Journal Information:
- Journal of Applied Physics, Journal Name: Journal of Applied Physics Journal Issue: 21 Vol. 119; ISSN JAPIAU; ISSN 0021-8979
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
GENERAL PHYSICS
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ABUNDANCE
ACCURACY
CAPACITANCE
COMPUTERIZED SIMULATION
CONCENTRATION RATIO
COOLING
COPPER SELENIDES
CROSS SECTIONS
DEFECTS
DENSITY
DISTRIBUTION
ELECTRIC POTENTIAL
GALLIUM SELENIDES
HOLES
ILLUMINANCE
INDIUM SELENIDES
METASTABLE STATES
RELAXATION