1064 nm InGaAs metamorphic laser power converts with over 44% efficiency

InGaAs metamorphic laser power converters (LPCs) have the potential to deliver electrical energy over distances of several kilometers. In this study, metalorganic chemical vapor deposition (MOCVD) was used to grow InGaAs-based LPCs with an absorption wavelength of 1064 nm. At step thicknesses of 2800 nm, overshoot thicknesses of 6000 nm, reverse component and thicknesses of 2.4% and 700 nm, respectively, a surface roughness of 6.0 nm and InGaAs (24%) lattice relaxation of 93.7% of the InGaAs metamorphic buffer were obtained. The I-V characteristics of LPCs with 10 × 10 mm² apertures were investigated as a function of laser power and temperature. The maximum conversion efficiency of 44.1% and 550 hours of continuous stable operation at 4 W were demonstrated. Under 1064 nm laser illumination of 4 W, the temperature coefficients for the conversion efficiency and open-circuit voltage were -0.1%abs/°C and -1.6 mV/°C, respectively, and the LPC output power fluctuation was less than 0.5% during 216 hours of continuous temperature change from 20 to 100°C.