Four-junction AlGaAs/GaAs laser power converter

Four-junction AlGaAs/GaAs laser power converters (LPCs) with n + -GaAs/p + -Al 0.37 Ga 0.63 As heterostructure tunnel junctions (TJs) have been designed and grown by metal-organic chemical vapor deposition (MOCVD) for converting the power of 808 nm lasers. A maximum conversion efficiency η c of 56.9% ± 4% is obtained for cells with an aperture of 3.14 mm 2 at an input laser power of 0.2 W, while dropping to 43.3% at 1.5 W. Measured current–voltage ( I – V ) characteristics indicate that the performance of the LPC can be further improved by increasing the tunneling current density of TJs and optimizing the thicknesses of sub-cells to achieve current matching in LPC.