Improvements in GaSb Homoepitaxial and IMF Solar Cells Grown via Metal-Organic Chemical Vapor Deposition

Current state of the art multijunction solar cells rely on a thick, metamorphic graded buffer from indium gallium arsenide (InGaAs) to gallium arsenide (GaAs) which accounts for nearly 30% of the total device cost. To make these devices more cost effective we propose an alternative, Sb based bottom junction material employing the interfacial mist (IMF technique), which allows for an immediate lattice constant transition. This technique causes dislocations to preferentially occur in the 90 degree plane rather than the 60 degree plane, mitigating dislocations that can degrade solar cell performance. The IMF technique has been heavily studied when grown via molecular beam epitaxy, whereas this work looks to move the technique to a higher throughput technique known as metal-organic chemical vapor deposition (MOCVD). Various parameters for gallium antimonide (GaSb) solar cells, both homoepitaxial and IMF, are studied. For IMF cells both buffer thickness and gallium precursor are studied