Journal de physique iii vol:2 issue:7 pages:1305-1316
The conversion efficiency of polycrystalline silicon solar cells has been raised to 15.6 % (for an area of 4 cm2), using simple processes to improve the base and the back and front surfaces. Spectral response measurements are presented and analyzed using a classical model, in order to reach the main physical parameters. It is found that the initial gettering procedure designed by Martinuzzi and Sarti raises the electron diffusion length in the base to values well above wafer thickness (180-mu-m); that owing to a p/p+ back junction, the back surface recombination rate is reduced to 10-10(2) cm/s; that owing to the emitter back-etching and passivation the front surface recombination rate is reduced to < 10(4) cm/s. These results explain the high efficiency. Improvement possibilities are discussed.