Progress in InP-based solar cells

Progress in the development of solar cells based on InP and its lower-energy-gap, lattice-matched family of Ga/sub x/In/sub 1-x/As/sub y/P/sub 1-y/ alloys is reviewed. The applications and performance of indium tin oxide (ITO)InP cells, monolithic tandem cells based on InP/Ga/sub 0.47/In/sub 0.53/As, mechanically stacked cells using GaAs/Ga/sub 0.25/In/sub 0.75/As/sub 0.54/P/sub 0.46/, and InP shallow-homojunction cells grown heteroepitaxially on lower-cost substrates are described. It is concluded that ITO/InP cells have reached a satisfactory efficiency level for 1-sun cells and are competitive with diffused-junction cells; mechanically stacked tandem concentrator cells have reached efficiencies that make them competitive with all other solar cells; monolithically grown tandem concentrator cells for space applications have the potential for significant improvements in efficiency; and heteroepitaxially grown InP homojunction cells hold considerable potential for space applications.<
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