Spectral analysis of the electroluminescence and photoresponse of heterostructures with InGaAs quantum objects

Abstract

Abstract In this work, physical and optical properties of In0.8Ga0.2As quantum dots (QDs) embedded in the structure of a single-junction GaAs solar cell (SC) grown by MOVPE technique were investigated using spectral characteristics of external quantum yield (EQE) and electroluminescence (EL). It has been found that, in characterizing QD physical parameters, simplified model of a thin stressed quantum well can be applied to a wetting layer (WL). It has been demonstrated that the EL spectra allows determining the absorption energy of photons in WL and QDs more accurately compared to the EQE spectra. Energies of “Ee-Ehh” and “Ee-Elh” transitions in WL have been determined and were 1.325 eV and 1.388 eV respectively. The calculated values of the WL thickness (5.63 Å) and In composition of QDs (xIn = 80%) coincide with the technological parameters used in the epitaxial growth of the device.