Si metal oxide semiconductor field effect transistors (MOSFETs) with the gate lengths of 120-300 nm have been studied as room temperature plasma wave detectors of 0.7 THz electromagnetic radiation. In agreement with the plasma wave detection theory, the response was found to depend on the gate length and the gate bias. The obtained values of responsivity (<= 200 V/W) and noise equivalent power (>= 10(-10) W/Hz(0.5)) demonstrate the potential of Si MOSFETs as sensitive detectors of terahertz radiation. (c) 2006 American Institute of Physics

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We report on the low frequency ͓1/ f and generation-recombination ͑GR͔͒ noise in InAlAs/InGaAs modulation doped field effect transistors with a 50-nm gate length. The characteristic capture and emission times of the GR noise depended on the gate voltage. Measurements of the noise as a function of the gate voltage showed that the gate leakage current, contacts, and ungated sections of the channel did not contribute to the 1 / f noise. The gate voltage dependence of the 1 / f noise agreed well with the model of number of carriers fluctuations as a source of the 1 / f noise. An effective density of traps responsible for the 1 / f noise was found to be D eff Ϸ 2.7ϫ 10 12 cm −2 eV −1 .

Detection of 100 GHz and 285 GHz electromagnetic radiation by GaAs/AlGaAs field effect transistors with the gate length of 150 nm was investigated at 300 K as a function of the angle α between the direction of linear polarization of the radiation and the symmetry axis of the field effect transistors. The angular dependence of the detected signal was found to be A cos 2 (α−α0)+C. A response of the transistor chip (including bonding wires and the substrate) to the radiation was numerically simulated. Calculations confirmed experimentally observed dependences and allowed to investigate the role of bonding wires and contact pads in coupling of the radiation to the transistor channel.