Submonolayer InGaAs/GaAs quantum dot solar cells

Optical and structural properties of submonolayer InGaAs/GaAs quantum dot solar cells (SML-QDSCs) are investigated and compared with quantum well solar cells (QWSCs). Compared with InGaAs/GaAs QWSCs with a similar structure, the material quality for SML QDSCs is significantly improved with a reduced density of both crosshatch patterns and defects. This coincides with a much higher photoluminescence intensity obtained for SML QDSCs. SML QDSCs thus exhibit an increase in open circuit voltage of 70 meV and an improvement in short circuit current from 15.9 mA/cm2 to 17.7 mA/cm2 in comparison with QWSCs. These findings present a promising alternative to quantum wells in photovoltaic applications.