Open Circuit Voltage Recovery in Quantum Dot Solar Cells: a Numerical Study on the Impact of Wetting Layer and Doping

The authors present a numerical study on the influence of wetting layer states and doping on the photovoltage loss of InAs/GaAs quantum dot solar cells. Quantum-mechanical simulations are used to analyse how the reduction of wetting layer by Al(Ga)As overgrowth changes the quantum dot electronic states. Device-level simulations allow to correlate such changes with the achievable open circuit voltage. Almost full open circuit voltage recovery is predicted by combining wetting layer reduction, to realise thermal decoupling of barrier and quantum dot confined states, and doping to suppress radiative recombination through the quantum dot confined states.