Defects in GaInNAs: What We've Learned So Far

We show results from a number of experimental and theoretical investigations on GaInNAs in an attempt to provide a more complete picture of defects in this material than is currently available. Much has been learned in recent years, including the effects of impurities such as hydrogen and carbon, the behavior of GaInNAs on annealing, and the defects that cause a degradation of materialproperties, including photoluminescence intensity and, especially important for solar cells, minority-carrier lifetimes. Much of our current understanding stems from a comparison of GaInNAs grown by both MOCVD and MBE. This comparison, along with the use of several characterization techniques and theoretical modeling, has allowed us to understand the roles of various defects and to identify asignature for the defect that reduces the minority-carrier lifetime.