Optical and electrical properties of InAs/GaAs quantum-dot solar cells

We investigated the optical and the electrical properties of InAs quantum-dot solar cells (QDSCs) with various InAs deposition thicknesses (θ) via photoluminescence (PL), spectral response (SR), and current density-voltage (J-V) measurements. We fabricated three QDSCs with thicknesses of 2.0, 2.5, and 3.0 monolayers (MLs). Our measurements revealed the effects of the QD size on the spectral response, the conversion efficiency (η) and the device parameters. The QDSCs had a maximum η of 17% for θ = 2.0 ML under AM1.5G conditions. The change of device parameters in various QDSCs could be explained by the effects of the balance between enhanced carrier production from the QD layers and carrier trapping/re-capturing by strain-induced defect/QD states.