Toward Realization of Silicon Solar Cells with High Efficiency(<Special Issue>Square-shaped Si Crystals for Solar Cell use)

Abstract

This paper discusses the determination factors of conversion efficiency in solar cells fabricated by silicon. The factors are impurity concentrations of light elements and heavy metals in a crystal, dislocation density and shape of a solid-liquid interface. A silicon multicrystal grown by a floating zone (FZ) method has about conversion efficiency with 80 to 90 percent of that in single crystalline silicon grown by FZ method. This result shows that the key point to obtain a high efficiency solar cell is to reduce impurity such as light elements and heavy metals, and dislocation.