Femtosecond and highly sensitive GaAs metal–semiconductor–metal photodetectors grown on aluminum mirrors/pseudo-substrates

In this study, ultrafast GaAs metal–semiconductor–metal (MSM) photodetectors grown on aluminum mirrors/pseudo-substrates were fabricated and tested. Surface characterization measurements revealed the good quality of the surface morphology, while x-ray diffraction measurements showed several crystallographic orientations of the GaAs layer. The material exhibited a 50 fs carrier lifetime due to growth-induced defects. The response of the photodetectors showed a full width at half maximum of 300 fs. These results demonstrate that the growth of GaAs layers on lattice-mismatched metallic substrates with high thermal conductivity is a promising approach for low-cost and large-area fabrication of electronic and ultrafast photonic devices that require a highly effective thermal drain.