1. Ultra-fast quantum-well infared photodetectors operating at 10{\mu}m with flat response up to 70GHz at room temperature
- Author
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Hakl, M., Lin, Q. Y., Lepillet, S., Billet, M., Lampin, J-F., Pirotta, S., Colombelli, R., Wan, W. J., Cao, J. C., Li, H., Peytavit, E., and Barbieri, S.
- Subjects
Physics - Applied Physics ,Physics - Instrumentation and Detectors ,Physics - Optics - Abstract
III-V semiconductor mid-infrared photodetectors based on intersubband transitions hold a great potential for ultra-high-speed operation up to several hundreds of GHz. In this work we exploit a ~350nm-thick GaAs/Al0.2Ga0.8As multi-quantum-well heterostructure to demonstrate heterodyne detection at 10um wavelength with a nearly flat frequency response up to 70GHz at room temperature, solely limited by the measurement system bandwidth. This is the broadest RF-bandwidth reported to date for a quantum-well mid-infrared photodetector. Responsivities of 0.15A/W and 1.5A/W are obtained at 300K and 77K respectively. To allow ultrafast operation and illumination at normal incidence, the detector consists of a 50Ohm coplanar waveguide, monolithically integrated with a 2D-array of sub-wavelength antennas, electrically interconnected by suspended wires. With this device architecture we obtain a parasitic capacitance of ~30fF, corresponding to the static capacitance of the antennas, yielding a RC-limited 3dB cutoff frequency >150GHz at 300K, extracted with a small-signal equivalent circuit model. Using this model, we quantitively reproduce the detector frequency response and find intrinsic roll-off time constants as low as 1ps at room temperature., Comment: The first version was updated, to correct some typos and add FigS5(b) to clarify the derivation of the detector circuit model
- Published
- 2020