GaSb/InGaAs quantum dot–well hybrid structure active regions in solar cells

► We have demonstrated the application of GaSb quantum dots in solar cells.
► A comparative study among dot, well and dot–well solar cells is presented.
► Quantum dot–well solar cells have shown superior infrared performance.
► An extended response up to 1265 nm is observed in QDW solar cell.
► GaSb QD sample shows the greatest strain-induced degradation of the emitter.

GaSb/InGaAs quantum dot–well (QDW) hybrid active regions with type-II band alignment are explored for increasing the infrared absorption in GaAs solar cells. Analyzed GaAs p–i–n structures comprise five layers of either GaSb quantum dot (QD), InGaAs quantum well (QW) or GaSb/InGaAs QDW layers in the i-region. It is found that the QDW solar cells outperform the QW and QD solar cells beyond GaAs band edge. In QDW solar cells an increase in efficiency is observed over QD solar cells due to additional QW absorption. An analysis of bulk response degradation in QDW solar cell is also presented. Improved photoresponse in QDW solar cells over QW and QD solar cells proves the potential for QDW hybrid structures in achieving high efficiency intermediate band solar cells.

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