High efficiency phototransducers based on a novel vertical epitaxial heterostructure architecture (VEHSA) with thin p/n junctions

This review outlines a series of developments in the design, modelling and growth of multi-junction laser power converters, including several observations of multi-junction GaAs monolithic vertical epitaxial heterostructure architecture devices with astonishing mono-chromatic optical to electrical conversion efficiencies in the 65–70% range. Experimental data is presented for devices ranging from single up to 20 p/n junctions, generally exhibiting weak dependence on source detuning which serves as evidence for strong photon recycling effects in these devices. Considerations for further design optimizations are discussed in detail, as well as the future direction of this research including the growth of devices with up to 100 subcells.