Title :
Recent developments in ZnO/CdS/CuGaSe2 single crystal solar cells
Author :
Saad, M. ; Riazi-Nejad, H. ; Bucher, E. ; Lux-Steiner, M.Ch.
Author_Institution :
Fakultat fur Phys., Konstanz Univ., Germany
Abstract :
An improvement of the power conversion efficiency of ZnO/CdS/CuGaSe2 single crystal solar cells was achieved by repetitive low temperature annealing. This resulted in a new improved efficiency of 6.7% (under 83 mW/cm2 AM 1.5 illumination), given by an open circuit voltage of 837 mV, a short circuit current density of 13.4 mA/cm2 and a fill factor of 50%. Diode characteristics with and without illumination were analysed. A reduced doping concentration within the CuGaSe2 absorber close to the CdS interface as well as an improved dark saturation current are made responsible for the efficiency enhancement. Photoluminescence spectra showed recombination on both sides of this interface. The results indicate that tunneling assisted by the defect levels in the CdS layer and a high series resistance still restrict the optimum device performance
Keywords :
II-VI semiconductors; annealing; cadmium compounds; copper compounds; electron-hole recombination; gallium compounds; p-n heterojunctions; semiconductor device testing; semiconductor doping; solar cells; ternary semiconductors; zinc compounds; 6.7 percent; 837 mV; CuGeSe2-CdS-ZnO; dark saturation current; defect levels; diode characteristics; doping concentration; efficiency enhancement; fill factor; interface; open circuit voltage; optimum device performance; photoluminescence spectra; recombination; repetitive low temperature annealing; series resistance; short circuit current density; single crystal solar cells; tunneling; Annealing; Diodes; Doping; Lighting; Photovoltaic cells; Power conversion; Short circuit currents; Temperature; Voltage; Zinc oxide;
Conference_Titel :
Photovoltaic Energy Conversion, 1994., Conference Record of the Twenty Fourth. IEEE Photovoltaic Specialists Conference - 1994, 1994 IEEE First World Conference on
Conference_Location :
Waikoloa, HI
Print_ISBN :
0-7803-1460-3
DOI :
10.1109/WCPEC.1994.519846
