Improved performance of multilayer InAs/GaAs quantum-dot solar cells using a high-growth-temperature GaAs spacer layer

The use of high-growth-temperature GaAs spacer layers is demonstrated to significantly enhance the performance of multilayer InAs/GaAs quantum-dot solar cells. Threading dislocations are observed for a 30-layer quantum-dot structure with GaAs spacer layers grown at low temperature (510 degrees C). The formation of threading dislocations is suppressed by growing the GaAs spacer layer at high temperature (580 degrees C), leading to enhanced quantum-dot optical and structural characteristics. Incorporation of the high-growth-temperature GaAs spacer layers into a 30-layer InAs/GaAs quantum-dot solar cell results in a dramatic increase in the short-circuit current compared to the one without the high-growth-temperature spacer layers and an increase in the short-circuit current compared to the reference GaAs solar cell. (C) 2012 American Institute of Physics. [doi:10.1063/1.3686184]