InGaAs/GaAs QD superlattices: MOVPE growth, structural and optical characterization, and application in intermediate-band solar cells

We report on the growth and characterization of InGaAs/GaAs quantum dot (QD) superlattices for application in intermediate-band solar cells (IBSCs). Good optical and structural quality QD superlattices with up to 50 periods were obtained by metal-organic vapor-phase epitaxy (MOVPE) growth on {113}B GaAs substrates. Solar cells containing Si ∂-doped and undoped QD superlattice absorption regions have been fabricated and their performance compared with control cells containing undoped GaAs or undoped InGaAs/GaAs superlattice absorption regions. The QD superlattice cells exhibited photoresponses extended to longer wavelengths than the control cells. The introduction of QDs to the absorbing region of the solar cells resulted in a decrease in the open-circuit voltages and, in some cases, a decrease in the short-circuit currents of the cells.