We study the microwave photo-response of a quantum point contact (QPC) formed on a GaAs/AlGaAs heterostructure with a high-electron-mobility two-dimensional electron gas. The QPCs are fabricated by two types of gates: a traditional split gate and a specially designed bridged gate. We observe a three orders of magnitude enhancement of the dark QPC conductance in the tunneling regime at the incident microwave power density of mW/cm2. The response of the bridged-gate structure is more than ten times larger than that of the split-gate QPC. This giant effect and the difference between the two types of gates are explained by the influence of microwaves on the steady-state electron distribution function in the vicinity of the tunnel contact. Experimental results are in good quantitative agreement with theoretical calculations. The bridged-gate QPC can be used for the creation of highly sensitive detectors of electromagnetic radiation.
Giant microwave photo-conductance of a tunnel point contact with a bridged gate
A. D. Levin, G. M. Gusev, Z. D. Kvon, A. K. Bakarov, N. A. Savostianova, S. A. Mikhailov, E. E. Rodyakina, A. V. Latyshev; Giant microwave photo-conductance of a tunnel point contact with a bridged gate. Appl. Phys. Lett. 17 August 2015; 107 (7): 072112. https://doi.org/10.1063/1.4928733
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