Comparative Analysis of the Optical and Physical Properties of InAs and In0.8Ga0.2As Quantum Dots and Solar Cells Based on them

InAs and In0.8Ga0.2As quantum dots in a GaAs matrix as well as GaAs solar cells with quantum dots of both types in the i-region are obtained by metalorganic vapor-phase epitaxy. As a result of investigations by photoluminescence and transmission electron microscopy, it is found that the In0.8Ga0.2As quantum-dot array is highly uniform, contains a smaller number of large imperfect quantum dots, and also provides a decrease in mechanical stresses in the structure. An analysis of the spectral dependences of the internal quantum yield shows that the quality of a solar-cell matrix after embedding up to 20 rows of In0.8Ga0.2As quantum dots remains at a level close to the reference GaAs solar cells. In this case, a linear increase in the additional photocurrent generated due to the absorption of sub-bandgap photons in In0.8Ga0.2As quantum dots is provided with an increase in the number of rows of quantum dots, since the value of the photocurrent gain per row is preserved.