Ref HAL: hal-00816972_v1
DOI: 10.1109/IRMMW-THz.2012.6380333
Exporter : BibTex | endNote
Résumé:

We have measured the Terahertz photoresponse of three types of FETs as a function of the temperature, to study the change of the dominant current mechanism. For all of them we have compared the photoresponse with its DC transfer characteristics, which is directly proportional to the conductivity.

DOI: 10.1063/1.4733465
WoS: 000306513400138
31 Citations
Résumé:

Temperature dependence of THz detection by field effect transistors was investigated in a wide range of temperatures from 275K down to 5 K. The important increase of the photoresponse following 1/T functional dependence was observed when cooling from room temperature down to 30K. At the temperatures below similar to 30 K, the THz response saturated and stayed temperature independent. Similar behavior was observed for GaAs, GaN, and Si based field effect transistors. The high temperature data were successfully interpreted using recent theory of overdamped plasma excitation in field effect transistors. The low temperature saturation of the photoresponse was tentatively explained by the change of the transport regime from diffusive to ballistic or traps governed one. Our results clearly show that THz detectors based on field effect transistors may improve their responsivity with lowering temperature but in the lowest temperatures (below similar to 30 K) further improvement is hindered by the physics of the electron transport itself.

Ref HAL: hal-00814487_v1
DOI: 10.1007/s10762-010-9647-7
WoS: 000290809100008
Exporter : BibTex | endNote
40 Citations
Résumé:

Resonant frequencies of the two-dimensional plasma in field effect transistors (FETs) increase with the reduction of the channel dimensions and can reach the Terahertz (THz) range. Nonlinear properties of the plasma/electron gas in the transistor channel can be used for the rectification and detection of THz radiation. The excitation of plasma waves by sub-THz and THz radiation was demonstrated for short gate transistors at cryogenic temperatures. At room temperature plasma oscillations are usually overdamped, but the FETs can still operate as efficient broadband rectifiers/detectors in the THz range. We present a few recent experimental results on THz detection by FETs showing some new ways of improvement of FETs for THz imaging at room temperature as well as the new physical phenomena like detection in quantizing magnetic fields. We also demonstrate THz emission properties of GaN based FETs.

Commentaires: , DOI = 10.1007/s10762-010-9647-7

Ref HAL: hal-00814188_v1
DOI: 10.1109/JSSC.2011.2165234
WoS: 000296234100017
Exporter : BibTex | endNote
116 Citations
Résumé:

A 2 x 2 array of 280-GHz Schottky-barrier diode detectors with an on-chip patch antenna (255 x 250 mu m(2)) is fabricated in a 130-nm logic CMOS process. The series resistance of diode is minimized using poly-gate separation (PGS), and exhibits a cut-off frequency of 2 THz. Each detector unit can detect an incident carrier with 100-Hz similar to 2-MHz amplitude modulation. At 1-MHz modulation frequency, the estimated voltage responsivity and noise equivalent power (NEP) of the detector unit are 250 V/W and 33 pW/Hz(1/2), respectively. An integrated low-noise amplifier further boosts the responsivity to 80 kV/W. At supply voltage of 1.2 V, the entire chip consumes 1.6 mW. The array occupies 1.5 x 0.8 mm(2). A set of millimeter-wave images with a signal-noise ratio of 48 dB is formed using the detector. These suggest potential utility of Schottky diode detectors fabricated in CMOS for millimeter wave and sub-millimeter wave imaging.

Ref HAL: hal-01922878_v1
DOI: 10.12693/APhysPolA.120.927
WoS: 000297714400032
Exporter : BibTex | endNote
Résumé:

We report on investigations of photovoltaic response of Si-MOSFETs subjected to terahertz radiation in high magnetic fields. Then a DC drain-to-source voltage is developed that shows singularities in magnetic fields corresponding to paramagnetic resonance conditions. These singularities are investigated as a function of incident frequency, temperature and two-dimensional carrier density. We tentatively attribute these resonances to spin transitions of the electrons bound to Si dopants and discuss the possible physical mechanism of the photovoltaic signal generation

Résumé:

We report on nonresonant detection of terahertz radiation using our original InGaP/InGaAs/GaAs plasmonresonant high-electron-mobility transistor having a dual grating gate (DGG) structure. The experiments were performed at room temperature using a Gunn diode operating at 0.30 THz as the THz source. Using a deviceloading model, the intrinsic responsivity was extracted and was dependent on the polarization of the incident THz wave. The device exhibited highest response when the electric-field vector of the incident THz radiation was directed in the source-drain direction. The 2D spatial distribution image of the transistor responsivity shows a clear beam focus centred on the transistor position, which proves the appropriate coupling of the THz radiation to the device, due to the DGG structure. The device also showed a high intrinsic responsivity of similar to 90 V/W and a noise equivalent power (NEP) as low as similar to 10-10 WHz(-0.5). (C) 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

Ref HAL: hal-00638518_v1
PMID 21503093
DOI: 10.1364/OE.19.007827
WoS: 000290482500081
Exporter : BibTex | endNote
282 Citations
Résumé:

This paper investigates terahertz detectors fabricated in a low-cost 130 nm silicon CMOS technology. We show that the detectors consisting of a nMOS field effect transistor as rectifying element and an integrated bow-tie coupling antenna achieve a record responsivity above 5 kV/W and a noise equivalent power below 10 pW/Hz(0.5) in the important atmospheric window around 300 GHz and at room temperature. We demonstrate furthermore that the same detectors are efficient for imaging in a very wide frequency range from similar to 0.27 THz up to 1.05 THz. These results pave the way towards high sensitivity focal plane arrays in silicon for terahertz imaging. (C) 2011 Optical Society of America