Advanced characterization by spectral cathodoluminiscence of 1eV GaInAs inverted metamorphic solar cells

Spectral cross-section cathodoluminescence has been used to characterize two equivalent 1eV GaInAs inverted metamorphic solar cells. The measurements reveal a slightly different composition between the GaInAs layers of both samples and the appearance of defects on one of them that is corroborated with external quantum efficiency and transmission electron microscopy. On the other hand, the measurements of the GaInP compositionally graded buffer exhibit a straight correlation between the decrease in the band gap energy and the formation of defects in the GaInAs layers. This work shows an alternative characterization method to perform a rapid quality control for the production of lattice-mismatched devices.