Incorporation of hydrogen into MBE-grown dilute nitride GaInNAsSb layers in a MOCVD growth ambient

Abstract

In this work, lattice-matched 3-junction and 4-junction solar cells including the dilute nitride subcells were fabricated by a hybrid growth technique of metalorganic chemical vapor deposition (MOCVD) and molecular beam epitaxy (MBE). It was found that photocarrier extraction in the MBE grown dilute nitride GaInNAsSb subcells degraded after the overgrowth of the upper subcells by MOCVD. Then, we focused on the effect of annealing for a set of MBE grown GaInNAsSb single junction solar cells annealed in the MOCVD reactor under an arsine flow ambient. It was found that degradation of the carrier extraction due to the MOCVD growth ambient is in a correlation with the selective hydrogen incorporation into the GaInNAsSb layers. We demonstrated that the subsequent annealing in nitrogen ambient promoted the outdiffusion of hydrogen which led to a recovery of the GaInNAsSb solar cell performances.