Internal electric fields of flexible gaas solar cells fabricated using epitaxial lift-off

Abstract

We have investigated the optical and electrical properties of flexible GaAs solar cells (SCs) fabricated by the epitaxial lift-off process using photoreflectance (PR) spectroscopy. The as-grown GaAs solar cells were transferred on Au/polyimide (ELA) and polydimethylsiloxane (PDMS; ELP) flexible substrates. In the PR spectra, low energy interference oscillations by internal multi-reflection were observed below the GaAs transition signals. The internal electric fields (Fint) were calculated to be 98.7 and 81.8 kV/cm for the ELA and ELP SCs, respectively. SCs produced by the ELA process exhibited fewer defects and higher Fint than the ELP SC.