Influence of InAs quantum dots on the transport properties of GaAs-based solar cell devices

• Comparative investigations of GaAs solar cells with and without InAs quantum dots.
• Trap states originated from quantum-dot-induced strain.
• Interface recombination mediated by tunneling process.
• Degradation of solar cell performance by quantum dots.

We investigated both the photovoltaic and transport properties of GaAs based solar cells with and without InAs quantum dots (QDs). In small forward bias region, humps in the local ideality factor are found in the QD-embedded devices at low temperatures. This might be caused by the charges captured in the QD-induced defect states. The temperature dependence of the ideality factor, extracted from large voltage regions, was well explained by the tunneling-mediated interface recombination process. The reverse-bias current also exhibited a signature of trap-mediated tunneling. All these results suggested that the presence of trap states could cause the degraded photovoltaic performance of our QD-embedded solar cells.