DocumentCode :
2507377
Title :
Modeling the effect of trap levels on the optimum resistivity of silicon solar cells
Author :
Smith, A.W. ; Rohatgi, A.
Author_Institution :
Sch. of Electr. Eng., Georgia Inst. of Technol., Atlanta, GA, USA
fYear :
1988
fDate :
1988
Firstpage :
729
Abstract :
Numerical studies were performed to determine the effect of different trap levels on the optimum resistivity required to produce high-efficiency solar cells from materials of varying initial quality. Lifetime decreases with the doping concentration due to Auger, band-to-band, and SRH (Shockley-Read-Hall) recombinations and shallow traps, make the SRH lifetime more sensitive to the doping density for the same initial lifetime in the undoped material. It was found that the optimum resistivity for high-efficiency cells depends on several factors including the initial lifetime, the trap level, the relationship between the trap and doping density and the injection level in the cell. For low initial lifetimes, around 10 mu s, the optimum resistivity is approximately 0.2 Omega -cm, regardless of the deep level location. In high-lifetime materials (10 ms), high injection level drives the optimum choice to high resistivity, 200 Omega -cm, regardless of the deep level location. For intermediate starting lifetimes (1000 mu s, 1 ms), location of the trap level can switch the optimum choice from low resistivity to high resistivity. It is shown that low resistivity is preferred for midgap deep levels, but high resistivity becomes desirable for shallow traps.
Keywords :
Auger effect; carrier lifetime; electrical conductivity of crystalline semiconductors and insulators; electron traps; electron-hole recombination; elemental semiconductors; semiconductor device models; silicon; solar cells; Auger recombination; Shockley-Read-Hall recombinations; Si solar cells; band-to-band recombination; doping concentration; doping density; lifetime; midgap deep levels; resistivity; semiconductor; shallow traps; trap levels; Charge carrier lifetime; Conductivity; Crystalline materials; Doping; Photovoltaic cells; Radiative recombination; Semiconductor materials; Semiconductor process modeling; Silicon; Switches;
fLanguage :
English
Publisher :
ieee
Conference_Titel :
Photovoltaic Specialists Conference, 1988., Conference Record of the Twentieth IEEE
Conference_Location :
Las Vegas, NV, USA
Type :
conf
DOI :
10.1109/PVSC.1988.105798
Filename :
105798
Link To Document :
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