Monolithic triple-junction $p$–$i$–$n$ AlGaAs/GaAs laser photoconverter

The photovoltaic characteristics of heterostructural triple-junction $p$–$i$–$n$ AlGaAs/GaAs photoconverters of monochromatic radiation grown by molecular-beam epitaxy in a single technological process have been studied. The spectral sensitivity of the created triple-junction photoconverters was in the wavelength range 0.78–0.87 $\mu$m. The achieved values of open circuit voltage 1.82 V and electrical power 0.34 mW/cm$^2$ in the photovoltaic mode at laser radiation power densities $\le$ 2 mW/cm$^2$ at a wavelength $\lambda$ = 850 nm exceed the characteristics of single-junction $p$–$i$–$n$ AlGaAs/GaAs photoconverters created by identical technology. The developed triple-junction photoconverters can be used in remote power systems for miniature microcircuits, in implantable bioelectronics and biosensors, as well as in long-term radioluminescent energy sources.