Wide bandgap solar cells for thin film tandem structures based on II-VI and I-III-VI2 compounds
Abstract
The development of thin film tandem solar cells is directed towards the realization of transparent wide bandgap top cells. For this purpose the promising binary and ternary chalcogenides and chalcopyrites are investigated. The preparation of CuGaSe2 thin films by vacuum-evaporation of the single elements is described. The electronic and optical properties of the films are related to the deviation from stoichiometry. First results of heterojunctions with (Zn,Cd)S yield 5 percent efficiency at AM 1.5 with a current density of 13 mA/sq cm and an open circuit voltage of 770 mV. V(oc) values of up to 970 mV have been realized. Both ZnTe-(Zn,Cd)S heterojunctions and Zn(Se,Te) graded homojunctions show quantum efficiencies up to 50 percent. In ZnTe-(Zn,Cd)S graded composition structures open circuit voltages of up to 1.43 V have been obtained.
- Publication:
-
IN: Photovoltaic Specialists Conference
- Pub Date:
- 1985
- Bibcode:
- 1985pvsp.conf.1671A
- Keywords:
-
- Band Structure Of Solids;
- Energy Gaps (Solid State);
- Heterojunctions;
- Solar Cells;
- Thin Films;
- Chalcogenides;
- Electrical Properties;
- Optical Properties;
- Electronics and Electrical Engineering