The growth of Si/sub x/Ge/sub 1-x/-crystals for infrared solar cell applications

Abstract

Monocrystalline Si/sub x/Ge/sub 1-x/ alloys may be a powerful material for infrared solar cell applications. In comparison with pure Si, Ruiz et al. (1994) have shown that SiGe-solar cells should increase their efficiency by 2% for x=0.5. However the optimum is quite broad and the maximum of this benefit may be reached with low Ge content cells. On the other hand the availability of a large quantity of SiGe-bulk crystals through the whole composition range is suitable for studies of fundamental properties of SiGe alloys. The present work focuses on new results in the growth of SiGe-single crystals prepared by two methods: (i) an RF-heated float zone-technique; and (ii) a conventional Czochralski-technique.