Resonant-cavity-enhanced heterostructure metal–semiconductor–metal photodetector

Abstract

We report a GaAs-based high-speed, resonant-cavity-enhanced, heterostructure metal–semiconductor–metal photodetector with Al0.24Ga0.76As/Al0.9Ga0.1As distributed Bragg reflector operating around 850 nm. The photocurrent spectrum shows a clear peak at this wavelength with full width at half maximum (FWHM) of around 30 nm. At resonance wavelength, a seven-fold increase can be achieved in quantum efficiency compared to a detector of the same absorption depth. The top reflector is a delta modulation doped Al0.24Ga0.76As that also acts as the barrier enhancement layer thus providing very low dark current values. The breakdown voltage is above 20 V. Time response measurements show rise time, fall time, and FWHM of 8.8 ps, 9 ps, and 8.1 ps, respectively, giving a 3-dB bandwidth of about 33 GHz. Combination of low dark current, fast response, wavelength selectivity, and compatibility with high electron mobility transistors makes this device especially suitable for short haul communications purposes.

Performance Enhancement of a GaAs Detector with a Vertical Field and an Embedded Thin Low-Temperature Grown Layer

“…The first is the vertical electric field produced by the GaAs/AlGaAs hetero-interface [14] and increased by the p-type delta-doping, which forces the optically generated electron up towards the interface, and the holes down through the LT region. The second is the existence of a 15 nm RT-GaAs channel that allows long recombination lifetimes and high mobility transport while also providing a good hetero-interface with AlGaAs unaffected by the deep defects of LT-GaAs.…”

Performance enhancement of photodetector using defect subwavelength metallic Grating

“…where h t is relation to the cavity mode in the slits, the two transmission coefficients can be expressed as: 12 1…”

“…Here, the defect SMG is considered as the top reflecting mirror of RCE structure. The quantum efficiency of RCE structure can be calculated employing the analytic expression as [12]: can bring out the maximum transmittance and quantum efficiency, simultaneously. Therefore, the maximum responsivity enhancement reaches 4.5, which is a substantial improvement over the uniform structure.…”

Light confinement and absorption in metal-semiconductor-metal nanostructures

“…8,9 On the other hand, RCE MSM photodetectors have been studied in order to increase the quantum efficiency with large finger spacing (> 1 µm). [10][11][12] In both cases, the bandwidth-efficiency product is limited by the opacity of the metallic electrodes. Among other photodetector designs, laterally illuminated waveguide and traveling-wave photodetectors 13,14 are other solutions for ultrafast devices.…”