Multiple-layered type-II GaSb/GaAs quantum ring solar cells under concentrated solar illumination

A multiple-layered type-II quantum ring nanostructure was embedded in the regular GaAs single junction solar cell to extend its infrared response. Three different designs were implemented and the location of quantum ring layers was investigated. Under one Sun condition, the n-type quantum ring device showed higher J_sc than the GaAs reference while the reduction of V_oc is minimum among all these quantum ring samples. Further tests through the filtered infrared light demonstrate the enhanced photo-currents from quantum ring devices. An increase as high as 292% in reverse-biased photocurrent can be observed.