  The thickness dependences of the photocurrent quantum yield and photoenergy
parameters of silicon backside contact solar cells (BC SC) are investigated
theoretically and experimentally. The surface recombination rate on the
irradiated surface was minimized by means of creating the layers of microporous
silicon. A method of finding the surface recombination rate and the diffusion
length of minority carriers from the thickness dependences of the photocurrent
quantum yield under conditions of the strong absorption is proposed. The
performed studies allowed us to establish that the thinning of the BC SC
samples in the case of minimizing the surface recombination rate gives a
possibility to achieve rather high efficiencies of photoconversion. It is also
shown that the agreement between the experimental and theoretical spectral
dependences of the photocurrent quantum yield can be reached only with regard
for the coefficient of light reflection from the backside surface.
