Impact of device resistances in the performance of graphene-based terahertz photodetectors.

In recent years, graphene field-effect-transistors (GFETs) have demonstrated an outstanding potential for terahertz (THz) photodetection due to their fast response and high-sensitivity. Such features are essential to enable emerging THz applications, including 6G wireless communications, quantum information, bioimaging and security. However, the overall performance of these photodetectors may be utterly compromised by the impact of internal resistances presented in the device, so-called access or parasitic resistances.

Terahertz Detection by Asymmetric Dual Grating Gate Bilayer Graphene FETs with Integrated Bowtie Antenna.

An asymmetric dual-grating gate bilayer graphene-based field effect transistor (ADGG-GFET) with an integrated bowtie antenna was fabricated and its response as a Terahertz (THz) detector was experimentally investigated. The device was cooled down to 4.5 K, and excited at different frequencies (0.

Nature of the 1/ noise in graphene-direct evidence for the mobility fluctuation mechanism.

The nature of the low-frequency 1/ noise in electronic materials and devices is one of the oldest unsolved physical problems ( is the frequency). The fundamental question of the noise source-fluctuations in the mobility . number of charge carriers-is still debated.

First Study on the Electronic and Donor Atom Properties of the Ultra-Thin Nanoflakes Quantum Dots.

Nanoflakes ultra-thin quantum dots are theoretically studied as innovative nanomaterials delivering outstanding results in various high fields. In this work, we investigated the surface properties of an electron confined in spherical ultra-thin quantum dots in the presence of an on-center or off-center donor impurity. Thus, we have developed a novel model that leads us to investigate the different nanoflake geometries by changing the spherical nanoflake coordinates (, α, ϕ).

Enhanced terahertz detection of multigate graphene nanostructures.

Terahertz (THz) waves have revealed a great potential for use in various fields and for a wide range of challenging applications. High-performance detectors are, however, vital for exploitation of THz technology. Graphene plasmonic THz detectors have proven to be promising optoelectronic devices, but improving their performance is still necessary.

Responsivity enhancement of a strained silicon field-effect transistor detector at 0.3 THz using the terajet effect.

We report on the enhancement of responsivity by more than one order of magnitude of a silicon-based sub-terahertz detector when a mesoscopic dielectric particle was used to localize incident radiation to a sub-wavelength volume and focus it directly onto the detector. A strained-silicon modulation field-effect transistor was used as a direct detector on an incident terahertz beam at 0.3 THz.

Numerical Study of the Coupling of Sub-Terahertz Radiation to n-Channel Strained-Silicon MODFETs.

This paper reports on a study of the response of a T-gate strained-Si MODFETs (modulation-doped field-effect transistor) under continuous-wave sub-THz excitation. The sub-THz response was measured using a two-tones solid-state source at 0.15 and 0.

Quantum nanoconstrictions fabricated by cryo-etching in encapsulated graphene.

We report on a novel implementation of the cryo-etching method, which enabled us to fabricate low-roughness hBN-encapsulated graphene nanoconstrictions with unprecedented control of the structure edges; the typical edge roughness is on the order of a few nanometers. We characterized the system by atomic force microscopy and used the measured parameters of the edge geometry in numerical simulations of the system conductance, which agree quantitatively with our low temperature transport measurements. The quality of our devices is confirmed by the observation of well defined quantized 2e/h conductance steps at zero magnetic field.

Sub-THz Imaging Using Non-Resonant HEMT Detectors.

Plasma waves in gated 2-D systems can be used to efficiently detect THz electromagnetic radiation. Solid-state plasma wave-based sensors can be used as detectors in THz imaging systems. An experimental study of the sub-THz response of II-gate strained-Si Schottky-gated MODFETs (Modulation-doped Field-Effect Transistor) was performed.

Room temperature detection of sub-terahertz radiation in double-grating-gate transistors.

Room temperature photovoltaic non-resonant detection by large area double-grating-gate InGaP/InGaAs/GaAs heterostructures was investigated in sub-THz range (0.24 THz). Semi-quantitative estimation of the characteristic detection length combined with self-consistent calculations of the electric fields excited in the structure by incoming terahertz radiation allowed us to interpret quantitatively the results and conclude that this detection takes place mainly in the regions of strong oscillating electric field excited in depleted portions of the channel.

Emission of terahertz radiation from dual grating gate plasmon-resonant emitters fabricated with InGaP/InGaAs/GaAs material systems.

This paper reviews recent advances in our original 2D-plasmon-resonant terahertz emitters. The structure is based on a high-electron-mobility transistor and featured with doubly interdigitated grating gates. The dual grating gates can alternately modulate the 2D electron densities to periodically distribute the plasmonic cavities along the channel, acting as an antenna.