Recombination Centers in Germanium

Abstract

The dependence of carrier lifetime in pure germanium upon injection level has been studied using a photoconductivity decay method. The data are analyzed in terms of the recombination theory for transient conditions including the case of high injection level. The results show that at least two recombination levels exist in pure germanium: one is active in n-type and the other in p-type. The recombination level in n-type germanium is at 0.28 eV from the conduction band and the cross section for capture of holes A_p is about 4.7 times larger than that for capture of electrons A_n. On the other hand, the recombination level in p-type germanium is at 0.25 eV from the valence band or 0.31 eV from the conduction band and A_n⁄A_p is about 9.8.