Title :
ZnTe insertion at the back contact of 1 μm-CdTe thin film solar cells
Author :
Amin, Nowshad ; Yamada, Akira ; Konagai, Makoto
Author_Institution :
Dept. of Electr. & Electron. Eng., Tokyo Inst. of Technol., Japan
Abstract :
N2 doped ZnTe was introduced at the back contact of 1 μm-CdTe absorbers to reduce the carrier recombination at the back contact of CdS/CdTe/Carbon/Ag configuration solar cells. ZnTe films were grown by MBE on GaAs and Corning glass substrates in order to investigate the characteristics of the films. Epitaxial growth of ZnTe was found on GaAs substrates and hole concentration of 8×1018 /cm3 with a resistivity of 0.045 Ω-cm was achieved when nitrogen doping was carried out by plasma source. On the contrary, poly-crystalline ZnTe films were grown on Corning glass and CdTe thin films. Both dark and photoconductivity of ZnTe films increased to 1.43×10-5 S/cm and 1.41×10-4 S/cm respectively, while the Zn to Te ratio was decreased to 0.25 during MBE growth. These ZnTe films were inserted with different thickness to close-spaced sublimation (CSS) grown 1 μm-thick CdTe solar cells. A conversion efficiency of 8.31% (Voc: 0.74 V, Jsc: 22.98 mA/cm2, FF: 0.49, area: 0.5 cm2) was achieved for 0.2 μm-ZnTe layer with a cell configuration of CdS/CdTe/ZnTe/Cu doped C/Ag
Keywords :
II-VI semiconductors; cadmium compounds; electrical contacts; electron-hole recombination; epitaxial growth; nitrogen; semiconductor device measurement; semiconductor device testing; semiconductor doping; semiconductor growth; semiconductor thin films; solar cells; sublimation; substrates; zinc compounds; 0.045 ohmcm; 0.2 mum; 0.74 V; 1 mum; 1.41E-4 S/cm; 1.43E-5 S/cm; 8.31 percent; CdTe; CdTe thin film solar cells; Corning glass; ZnTe:N2; ZnTe:N2 back contact; carrier recombination reduction; close-spaced sublimation; dark conductivity; epitaxial growth; hole concentration; nitrogen doping; photoconductivity; resistivity; substrates; Conductivity; Epitaxial growth; Gallium arsenide; Glass; Molecular beam epitaxial growth; Nitrogen; Photovoltaic cells; Substrates; Transistors; Zinc compounds;
Conference_Titel :
Photovoltaic Specialists Conference, 2000. Conference Record of the Twenty-Eighth IEEE
Conference_Location :
Anchorage, AK
Print_ISBN :
0-7803-5772-8
DOI :
10.1109/PVSC.2000.915928
