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Proceedings Paper

Two-dimensional model for high-efficiency microgroove silicon solar cells
Author(s): M. Abdus Sobhan; M. Nurul Islam
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Paper Abstract

Fabrication of high efficiency (approximately equals 25%) micro-groove ((mu) g) silicon solar cell (Fig. 1) has been reported. In this cell structure, the p-n junction to collect photo-carriers are parallel to the illuminated surface but the carrier movement normal to the (111) junction planes contribute to the photo-current only. A 2-D device model is therefore proposed for analysis of this cell. The optical generation rate (OGR) is obtained by a ray-tracing algorithm (RTA). By Fourier transform, a 2-D OGR formula is developed on the basis of the numerical data from the RTA. With appropriate boundary conditions and the 2-D OGR formula, the relevant transport equations are solved. Expressions for minority carrier and photo-current densities have been derived and, to evaluate the cell performance parameters, a computer code has been developed. Computer simulation shows a maximum efficiency of 25.5% at AMO, 135.3 mW/cm2 and 26.4% at AM1.5, 100 mW/cm2, which are well within reach of the present VLSI technology. The theoretical results obtained from the code are compared with the experimental values. Effects of cell thickness, base doping level, junction depth, and surface recombination velocities on cell performance parameters have been studied. The efficiency is found to maximize at about 100 micrometers cell thickness and at a junction depth of about 0.1 micrometers . It is found that the (mu) g-cell efficiency is less sensitive to change in junction depth. To test the proposed 2-D model, the boundary conditions and the current density expressions are compared with those of a planar cell of the same thickness. As groove angle 0 (54.75 deg for (mu) g-cells) tends to zero, all the boundary conditions and the current density expressions reduce to the corresponding ones for the planar structure.

Paper Details

Date Published: 1 December 1991
PDF: 12 pages
Proc. SPIE 1536, Optical Materials Technology for Energy Efficiency and Solar Energy Conversion X, (1 December 1991); doi: 10.1117/12.49232
Show Author Affiliations
M. Abdus Sobhan, Univ. of Rajshahi (Bangladesh)
M. Nurul Islam, Univ. of Rajshahi (Bangladesh)

Published in SPIE Proceedings Vol. 1536:
Optical Materials Technology for Energy Efficiency and Solar Energy Conversion X
Carl M. Lampert; Claes G. Granqvist, Editor(s)

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