Preserving voltage and long wavelength photoresponse in GaSb/GaAs quantum dot solar cells

Improvement in the open circuit voltage of the GaSb/GaAs quantum dot intermediate band solar cell is achieved by compensating thermionic hole emission of the quantum dots with n-type doping while the short circuit current decreases due to reduced absorption and/or carrier collection. A new QD-IBSC design with a graded doping profile is studied where the QD layers are located at the edge of the space charge region. The built-in electric field provides enhanced photoresponse while preserving solar cell voltage.