Enhanced photocurrent due to interband transitions from InAs quantum dots embedded in InGaAs quantum well solar cells

Abstract

ABSTRACTSolar cells based on InAs quantum dots embedded in InxGa1-xAs quantum wells grown on n-type GaAs substrate were fabricated and tested. Solar cells with In mole fraction (x) in the range of 0-40% were investigated. The performance of the solar cells was evaluated using current-voltage characteristics, spectral response, and quantum efficiency measurements. The spectral response and quantum efficiency spectra possess several peaks along the lower energy side of the spectra, which are attributed to the interband transitions in the structure. These peaks are red shifted as x is increased above 0 %. The device power conversion efficiency was extracted from the current-voltage characteristics using an AM 1.5 solar simulator. The short circuit current density increased as the x is increased above 0 %. But the overall power conversion efficiency decreased due to decrease in the open circuit voltage. The decrease in open circuit voltage is due strain induced dislocations caused by lattice mismatch.