Enhancement of photocurrent in epitaxial lift-off thin-film GaInNAsSb solar cells due to light-confinement structure

Abstract

This work focuses on the characterization of GaInNAsSb solar cells whose substrates are removed via the epitaxial lift-off (ELO) technique. As a result of the substrate removal, increases in the photocurrent and the interference feature were clearly observed. This is clear evidence of the lightconfinement effect, whereby some of the unabsorbed photons at the rear metal contact were reflected back towards the front side of the ELO thinfilm cell. We successfully demonstrated that the ELO technique can be applied for the GaInNAsSb cell, and the light management should add flexibility in designing the cell structures.