Bound-to-continuum intraband transition properties in InAs/GaAs quantum dot superlattice solar cells

Abstract

We studied the interband and intraband excitation densities and the polarization dependent photocurrent in InAs/GaAs quantum dot superlattice (QDSL) solar cells with a built-in electric field of 5 kV cm-1. An almost polarization-insensitive intraband transition was observed for normal incident light, whereas slight anisotropy in the intraband transition resulted from the mixing between the conduction and valence bands. Furthermore, saturable two-color photocurrent was observed in the p-i-n solar-cell device because of electron transport in the QDSL miniband.