As-Grown InGaAsN Subcells for Multijunction Solar Cells by Molecular Beam Epitaxy (2021)
Journal of Photovoltaics - 2021 - M. Levillayer
In this article, we investigate the molecular beam epitaxy growth of unannealed 1.12 eV InGaAsN solar cells. The impact of the growth temperature, the As/III ratio and the bismuth used as a surfactant are reported. An in-situ curvature measurement setup enables to monitor and ensures a constant N incorporation during the InGaAsN growth. Ex-situ characterization results suggest that a high As/III ratio ensures good optoelectronic properties and that the growth temperature has a strong influence on the residual doping of the dilute nitride layer. Under AM0 > 870 nm and without antireflection coatings, our best InGaAsN solar cells exhibit J sc and V oc values of 7.94 mA/cm 2 and 0.375 V, respectively. Considering no internal reflection and no grid shading, generation up to 12 mA/cm 2 in a multijunction solar cell can be expected, which is the highest value ever reported for As-grown InGaAsN cells to our knowledge.
