High-Performance Multi-Junction C-Band Photonic Power Converters: Calibrated Optoelectronic Model for Next Generation Designs

Predicting behavior of optoelectronic devices is critical for device design and optimization. Such predictions can be made with a calibrated drift-diffusion model. Recently, photovoltaics using InGaAs as the absorber material, lattice matched to InP, have shown excellent performance in many applications. Further enhancements may be possible by optimizing the designs with an optoelectronic model, calibrated to results from experimental devices. We characterize fabricated InGaAs photonic power converters (PPCs) that have 60 nm, 180 nm, and 540 nm absorber layer thicknesses, using experimental results to calibrate our drift-diffusion model. The calibrated model predicts external quantum efficiencies to better than 1% accuracy and overestimates the open-circuit voltage under 1540 nm illumination by less than 2%. Using this calibrated model, we predict a realistic 1-junction PPC efficiency of up to 46% for a 1540 nm laser, with efficiency limited by carrier collection and series resistance. Improved junction architecture and cell segmentation could help to mitigate both issues. We also fabricated and characterized a 10-junction PPC made of series-connected InGaAs subcells and measured a maximum efficiency of 44% under 1540 nm illumination at 33 W/cm2 power with an open-circuit voltage above 5 V, providing both high efficiency and the voltage required to power electronic circuitry.