In$_{0.8}$Ga$_{0.2}$As quantum dots for GaAs solar cells: metal-organic vapor-phase epitaxy growth peculiarities and properties

The growth peculiarities of In$_{0.8}$Ga$_{0.2}$As quantum dots and their arrays on GaAs surface by metalorganic vapor-phase epitaxy are investigated. The bimodal size distribution of In$_{0.8}$Ga$_{0.2}$As quantum dots is established from the photoluminescence spectra recorded at different temperatures. The growth parameters were determined at which the stacking of 20 In$_{0.8}$Ga$_{0.2}$As quantum-dot layers in the active area of a GaAs solar cell makes it possible to enhance the photogenerated current by 0.97 and 0.77 mA/cm$^2$ for space and terrestrial solar spectra, respectively, with the high quality of the $p$–$n$ junction retained. The photogenerated current in a solar cell with quantum dots is higher than in the reference GaAs structure by $\sim$1% with regard to nonradiative-recombination loss originating from stresses induced by the quantum-dot array.