Title :
N-type multicrystalline silicon: a stable, high lifetime material
Author :
Cuevas, A. ; Riepe, S. ; Kerr, M.J. ; Macdonald, D.H. ; Coletti, G. ; Ferrazza, F.
Author_Institution :
Fac. of Eng., Australian Nat. Univ., Canberra, ACT, Australia
Abstract :
An investigation of n-type multicrystalline silicon grown by directional solidification has produced several important findings: i) demonstration of effective phosphorus gettering; ii) achievement of minority carrier lifetimes above one millisecond; iii) verification of good stability under illumination. The lifetimes after gettering show a strong dependence on doping: 1.6 ms for 2.3 /spl Omega/cm, 500 /spl mu/s for 0.9 /spl Omega/cm and 100 /spl mu/s for 0.36 /spl Omega/cm, respectively. Lifetime mapping by infrared carrier density imaging has revealed a large surface variability of this parameter, which is detrimental for large area devices. A minor degradation of the lifetime after light exposure has been observed for the highest lifetime regions, while other wafers and regions remained essentially stable.
Keywords :
carrier density; carrier lifetime; directional solidification; elemental semiconductors; getters; minority carriers; phosphorus; silicon; solar cells; 0.36 ohmcm; 0.9 ohmcm; 1.6 ms; 100 mus; 2.3 ohmcm; 500 mus; P; Si; directional solidification; doping; infrared carrier density imaging; lifetime mapping; minor degradation; minority carrier; n-type multicrystalline silicon; phosphorus gettering; solar cell; surface variability; wafers;
Conference_Titel :
Photovoltaic Energy Conversion, 2003. Proceedings of 3rd World Conference on
Conference_Location :
Osaka, Japan
Print_ISBN :
4-9901816-0-3
