GaSb/InGaAs quantum dot-well solar cells

GaSb/InGaAs quantum dot-well (QDW) hybrid active regions with type-II band alignment are explored for increasing infrared absorption in GaAs solar cells. GaAs p-i-n structures studied in this work comprise five layers of either GaSb quantum dots (QD), InGaAs quantum wells (QW) or GaSb/InGaAs QDWs in the i-region. The QDW solar cells exhibited superior performance beyond the GaAs band edge compared to the QW and QD solar cells. In QDW solar cells improved efficiency is observed over QD solar cells due to additional QW absorption. An analysis of bulk response degradation in a QDW solar cell is also presented. Improved photo response in QDW solar cells over QW and QD solar cells proves the potential of QDW hybrid structures for realizing high efficiency intermediate band solar cells.