New Manufacturing Approaches to Texture Formation and Thermal Expansion Matching in the Design of Highly Efficient Silicon Solar Photoconverters

Abstract

The causes of the failure of highly efficient silicon solar photoconverters are considered. About 30% of failures take place because of crack formation in silicon wafers and electrodes. Mechanical stresses leading to crack formation are associated with the pyramidal texture geometry and difference in the thermal expansion of the construction materials. A new procedure for silicon texturing is described, where SiO_x precipitates perform the function of texture nuclei, which makes it possible to obtain a surface consisting of submicron concave spheroids, which sharply decreases reflection in the wavelength region of 330–550 nm. A new method of matching the thermal expansion of photoconverter design elements with the use of matching layers of iron–nickel alloys is proposed, which provides a substantial decrease in the failure probability by the crack-formation mechanism in silicon wafers and the delamination of electrodes.