Persistent photoconductivity in Cu(In,Ga)Se2 heterojunctions and thin films prepared by sequential deposition
Abstract
A characteristic, reversible metastability is observed for Cu(In,Ga)Se2 thin films and ZnO/CdS/Cu(In,Ga)Se2 heterojunctions. Annealing at 80 °C leads to a decrease of the dark conductivity of the thin films by up to a factor of 2 at room temperature and several orders of magnitude when measured at lower temperatures. By exposure to light, the initial state can be re-established. This reenhancement of the dark conductivity can be looked at as persistent photoconductivity. Admittance measurements at Cu(In,Ga)Se2 heterojunction solar cells display a reversible shift of the activation energy of a distinct dielectric loss peak ranging from 70 to about 160 meV upon illumination or annealing at 80 °C, respectively. We propose that both phenomena as well as commonly observed light-soaking effects of Cu(In,Ga)Se2 solar cells have a common origin.
- Publication:
-
Applied Physics Letters
- Pub Date:
- July 1998
- DOI:
- 10.1063/1.121762
- Bibcode:
- 1998ApPhL..73..223R
- Keywords:
-
- 73.61.Le;
- 73.50.Pz;
- 84.60.Jt;
- 73.40.Lq;
- Other inorganic semiconductors;
- Photoconduction and photovoltaic effects;
- Photoelectric conversion: solar cells and arrays;
- Other semiconductor-to-semiconductor contacts p-n junctions and heterojunctions