Characterization of InGaP heterojunction emitter quantum dot solar cells

Abstract

Heterojunction emitter InAs/GaAs quantum dot solar cells (QDSC) with an In0.48Ga0.52P (InGaP) n-type emitter and p-type GaAs base were fabricated along with homojunction nip solar cells in order to enable sub-cell polarity compatibility of InAs/GaAs QDSCs with current state-of-the-art monolithic InGaP/GaAs/Ge triple junction solar cells for space applications and to investigate potential dark current suppression effects and electronic field enhancement effects on carrier collection in InAs/GaAs QDSC. Quantum dot solar cells with one-Sun AM0 open circuit voltages greater than 970 mV were fabricated as compared to a 1.020 V heterojunction emitter `control' sample. Preliminary testing showed a reduction in short circuit current density from homojunction to heterojunction GaAs solar cells, primarily from changes in reflection and uncollected absorption in the InGaP emitter.