Physics Commons^™

Growth Of Metamorphic Ingap For Wide-Bandgap Photovoltaic Junction By Mbe, John Simon, Stephanie Tomasulo, Paul J. Simmonds, Manuel J. Romero, Minjoo Larry Lee

Paul J. Simmonds

Metamorphic triple-junction solar cells can currently attain efficiencies as high as 41.1%. Using additional junctions could lead to efficiencies above 50%, but require the development of a wide bandgap (2.0-2.2eV) material to act as the top layer. In this work we demonstrate wide bandgap In_yGa_1-yP grown on GaAs_xP_1-x via solid source molecular beam epitaxy. Unoptimized tensile GaAs_xP_1-x buffers grown on GaAs exhibit asymmetric strain relaxation, along with formation of faceted trenches 100-300 nm deep in the [01-1] direction. Smaller grading step size and higher substrate temperatures minimizes the facet trench …