scholarly journals Thermoelectric graphene photodetectors with sub-nanosecond response times at terahertz frequencies

Nanophotonics ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 89-98 ◽  
Author(s):  
Leonardo Viti ◽  
Alisson R. Cadore ◽  
Xinxin Yang ◽  
Andrei Vorobiev ◽  
Jakob E. Muench ◽  
...  
Keyword(s):  
High Speed ◽  
Room Temperature ◽  
Coherent Control ◽  
Response Times ◽  
Field Effect Transistors ◽  
High Sensitivity ◽  
Far Infrared ◽  
Noise Equivalent Power ◽  
Thz Spectroscopy ◽  
Time Resolved

AbstractUltrafast and sensitive (noise equivalent power <1 nW Hz−1/2) light-detection in the terahertz (THz) frequency range (0.1–10 THz) and at room-temperature is key for applications such as time-resolved THz spectroscopy of gases, complex molecules and cold samples, imaging, metrology, ultra-high-speed data communications, coherent control of quantum systems, quantum optics and for capturing snapshots of ultrafast dynamics, in materials and devices, at the nanoscale. Here, we report room-temperature THz nano-receivers exploiting antenna-coupled graphene field effect transistors integrated with lithographically-patterned high-bandwidth (∼100 GHz) chips, operating with a combination of high speed (hundreds ps response time) and high sensitivity (noise equivalent power ≤120 pW Hz−1/2) at 3.4 THz. Remarkably, this is achieved with various antenna and transistor architectures (single-gate, dual-gate), whose operation frequency can be extended over the whole 0.1–10 THz range, thus paving the way for the design of ultrafast graphene arrays in the far infrared, opening concrete perspective for targeting the aforementioned applications.

Evaluation Humidity Sensing Properties of Graphene/HS-TiO2 Nanocomposites

2021 ◽  
Vol 21 (10) ◽  
pp. 5143-5149
Author(s):  
Zhen Zhu ◽  
Wang-De Lin
Keyword(s):  
Room Temperature ◽  
Response Times ◽  
Sol Gel ◽  
Hollow Spheres ◽  
High Sensitivity ◽  
Humidity Sensing ◽  
X Ray ◽  
Transmission Electron ◽  
Recovery Times ◽  
Relative Humidity Range

This paper reports on a nanocomposite synthesized by sol–gel procedure comprising graphene sheets with hollow spheres of titanium dioxide (G/HS-TiO2) with varying weight percentages of graphene for the purpose of humidity sensors. The surface morphology of the nanocomposite was characterized using transmission electron microscopy (TEM) and energy dispersive X-ray spectroscopy (EDX). The structural properties were examined using X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FTIR). The response to 12–80% RH at room temperature exhibited sensitivity (S = 135). However, the relative humidity range of 12–90% at room temperature exhibited higher sensitivity (S = 557). Sensors fabricated using the proposed nanocomposite exhibited high sensitivity to humidity, high stability, rapid response times, and rapid recovery times with hysteresis error of less than 1.79%. These results demonstrate the outstanding potential of his material for the monitoring of atmospheric humidity. This study also sought to elucidate the mechanisms underlying humidity sensing performance.

scholarly journals High-speed black phosphorus field-effect transistors approaching ballistic limit

2019 ◽  
Vol 5 (6) ◽  
pp. eaau3194 ◽  
Author(s):  
Xuefei Li ◽  
Zhuoqing Yu ◽  
Xiong Xiong ◽  
Tiaoyang Li ◽  
Tingting Gao ◽  
...  
Keyword(s):  
High Speed ◽  
Room Temperature ◽  
Field Effect Transistors ◽  
Ballistic Transport ◽  
Black Phosphorus ◽  
Saturation Velocity ◽  
High Drive ◽  
High Carrier Mobility ◽  
High Carrier ◽  
Strong Candidate

As a strong candidate for future electronics, atomically thin black phosphorus (BP) has attracted great attention in recent years because of its tunable bandgap and high carrier mobility. Here, we show that the transport properties of BP device under high electric field can be improved greatly by the interface engineering of high-quality HfLaO dielectrics and transport orientation. By designing the device channels along the lower effective mass armchair direction, a record-high drive current up to 1.2 mA/μm at 300 K and 1.6 mA/μm at 20 K can be achieved in a 100-nm back-gated BP transistor, surpassing any two-dimensional semiconductor transistors reported to date. The highest hole saturation velocity of 1.5 × 107 cm/s is also achieved at room temperature. Ballistic transport shows a record-high 36 and 79% ballistic efficiency at room temperature and 20 K, respectively, which is also further verified by theoretical simulations.

High-Speed Room Temperature Terahertz Detectors Based on InP Double Heterojunction Bipolar Transistors

2016 ◽  
Vol 25 (03n04) ◽  
pp. 1640011 ◽  
Author(s):  
D. Coquillat ◽  
V. Nodjiadjim ◽  
S. Blin ◽  
A. Konczykowska ◽  
N. Dyakonova ◽  
...  
Keyword(s):  
Heterojunction Bipolar Transistors ◽  
High Speed ◽  
Room Temperature ◽  
High Sensitivity ◽  
Low Noise ◽  
Bipolar Transistors ◽  
Low Noise Amplifiers ◽  
Modulation Bandwidth ◽  
Terahertz Detection ◽  
Double Heterojunction

Compact and fast detectors, for imaging and wireless communication applications, require efficient rectification of electromagnetic radiation with frequencies approaching 1 THz and modulation bandwidth up to a few tens of GHz. This can be obtained only by using a mature technology allowing monolithic integration of detectors with low-noise amplifiers. One of the best candidates is indium phosphide bipolar transistor (InP HBT) technology. In this work, we report on room temperature high sensitivity terahertz detection by InP double-heterojunction bipolar transistors (DHBTs) operating in a large frequency range (0.25–3.1 THz). The performances of the DHBTs as terahertz sensors for communications were evaluated showing the modulation bandwidth of investigated DHBTs close to 10 GHz.

Sub-THz radiation room temperature sensitivity of long-channel silicon field effect transistors

2012 ◽  
Vol 20 (2) ◽  
Author(s):  
F. Sizov ◽  
A. Golenkov ◽  
D. But ◽  
M. Sakhno ◽  
V. Reva
Keyword(s):  
Field Effect ◽  
Room Temperature ◽  
Field Effect Transistors ◽  
Cmos Technology ◽  
Effective Area ◽  
Noise Equivalent Power ◽  
Thz Radiation ◽  
Si Substrates ◽  
Temperature Operating ◽  
Long Channel

AbstractRoom temperature operating n-MOSFETs (n-type metal-oxide silicon field effect transistors) used for registration of sub-THz (sub-terahertz) radiation in the frequency range ν = 53−145 GHz are considered. n-MOSFETs were manufactured by 1-μm Si CMOS technology applied to epitaxial Si-layers (d ≈15 μm) deposited on thick Si substrates (d = 640 μm). It was shown that for transistors with the channel width to length ratio W/L = 20/3 μm without any special antennas used for radiation input, the noise equivalent power (NEP) for radiation frequency ν ≈76 GHz can reach NEP ∼6×10−10 W/Hz1/2. With estimated frequency dependent antenna effective area Sest for contact wires considered as antennas, the estimated possible noise equivalent power NEPpos for n-MOSFET structures themselves can be from ∼15 to ∼103 times better in the specral range of ν ∼55–78 GHz reaching NEPpos ≈10−12 W/Hz1/2.

Field Effect Transistors of BTQBT and its Derivatives

2002 ◽  
Vol 725 ◽  
Author(s):  
Masaki Takada ◽  
Yoshiro Yamashita ◽  
Hirokazu Tada
Keyword(s):  
Field Effect ◽  
High Speed ◽  
Room Temperature ◽  
Film Growth ◽  
Field Effect Transistors ◽  
Growth Conditions ◽  
Organic Transistors ◽  
Semiconducting Material ◽  
P Type

AbstractWe have prepared and characterized thin film field effect transistors (FETs) of bis-(1, 2, 5-thiadiazolo)-p-quinobis(1, 3-dithiole) (BTQBT) and its derivatives. Preparation and characterization of the films were carried out under ultrahigh vacuum condition. Most materials examined showed p-type semiconducting behaviors. Among p-type molecules, BTQBT films deposited at room temperature showed the highest mobility and on/off ratio of 0.2 cm2/Vs and 108, respectively, at optimal film growth conditions. These performances are almost comparable to those of pentacene and polythiophene thin films, indicating that BTQBT molecule is a prominent semiconducting material for high-speed organic transistors. It was also found that a tetracyanoquinodimethane (TCNQ) derivative showed an n-type semiconducting behavior with an electron mobility of 8.9 x 10-4 cm2/Vs.

scholarly journals Ultrafast correlated charge and lattice motion in a hybrid metal halide perovskite

2019 ◽  
Vol 5 (5) ◽  
pp. eaaw5558 ◽  
Author(s):  
Yang Lan ◽  
Benjamin J. Dringoli ◽  
David A. Valverde-Chávez ◽  
Carlito S. Ponseca ◽  
Mark Sutton ◽  
...  
Keyword(s):  
Room Temperature ◽  
Longitudinal Optical ◽  
Metal Halide ◽  
Thz Spectroscopy ◽  
Time Resolved ◽  
Carrier Lifetimes ◽  
Metal Halide Perovskite ◽  
Coherent Coupling ◽  
Halide Perovskites ◽  
Correlated Motion

Hybrid organic-inorganic halide perovskites have shown remarkable optoelectronic properties, exhibiting an impressive tolerance to defects believed to originate from correlated motion of charge carriers and the polar lattice forming large polarons. Few experimental techniques are capable of directly probing these correlations, requiring simultaneous sub–millielectron volt energy and femtosecond temporal resolution after absorption of a photon. Here, we use time-resolved multi-THz spectroscopy, sensitive to the internal excitations of the polaron, to temporally and energetically resolve the coherent coupling of charges to longitudinal optical phonons in single-crystal CH3NH3PbI3 (MAPI). We observe room temperature intraband quantum beats arising from the coherent displacement of charge from the coupled phonon cloud. Our measurements provide strong evidence for the existence of polarons in MAPI at room temperature, suggesting that electron/hole-phonon coupling is a defining aspect of the hybrid metal-halide perovskites contributing to the protection from scattering and enhanced carrier lifetimes that define their usefulness in devices.

Theoretical Comparison of 3C-SiC and Si Nanowire FETs in Ballistic Regime

2008 ◽  
Vol 600-603 ◽  
pp. 579-582 ◽  
Author(s):  
Konstantinos Rogdakis ◽  
Marc Bescond ◽  
Edwige Bano ◽  
Konstantinos Zekentes
Keyword(s):  
High Speed ◽  
Room Temperature ◽  
Field Effect Transistors ◽  
Electronic Devices ◽  
Subthreshold Slope ◽  
Electrical Behavior ◽  
Ballistic Regime ◽  
Si Nanowire ◽  
The Poisson Equation ◽  
Hostile Environments

3C-SiC is a promising material for high power and high-speed electronic devices as well as in sensors operating at high temperatures or hostile environments. For these reasons, we solved self-consistently the Poisson equation within the quantum Non Equilibrium Green Function Formalism (NEGF) in order to model and compare 3C-SiC and Si nanowire (NW) Field Effect Transistors (FETs) operating in ballistic regime (at room temperature 300 K). As a general conclusion of our calculations, Si and SiC NW FETs have almost the same electrical behavior: they depict the same subthreshold slope and have similar on currents [ION/IOFF (SiC)~81 % ION/IOFF (Si) in case of 4 nm NW cross section side].

scholarly journals Semiconductor Nanowire Field-Effect Transistors as Sensitive Detectors in the Far-Infrared

Nanomaterials ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 3378
Author(s):  
Mahdi Asgari ◽  
Leonardo Viti ◽  
Valentina Zannier ◽  
Lucia Sorba ◽  
Miriam Serena Vitiello
Keyword(s):  
Room Temperature ◽  
Field Effect Transistors ◽  
Far Infrared ◽  
Detection Mechanism ◽  
Semiconductor Nanowire ◽  
Electrostatic Gating ◽  
Inas Nanowires ◽  
Quantum Science ◽  
On Chip ◽  
Infrared Frequencies

Engineering detection dynamics in nanoscale receivers that operate in the far infrared (frequencies in the range 0.1–10 THz) is a challenging task that, however, can open intriguing perspectives for targeted applications in quantum science, biomedicine, space science, tomography, security, process and quality control. Here, we exploited InAs nanowires (NWs) to engineer antenna-coupled THz photodetectors that operated as efficient bolometers or photo thermoelectric receivers at room temperature. We controlled the core detection mechanism by design, through the different architectures of an on-chip resonant antenna, or dynamically, by varying the NW carrier density through electrostatic gating. Noise equivalent powers as low as 670 pWHz−1/2 with 1 µs response time at 2.8 THz were reached.

TEM study of phosphorus-implanted pseudomorphic Si0.88Ge0.12 on Si(100)

1995 ◽  
Vol 53 ◽  
pp. 468-469
Author(s):  
N. David Theodore ◽  
Donald Y.C Lie ◽  
J. H. Song ◽  
Peter Crozier
Keyword(s):  
Integrated Circuits ◽  
Heterojunction Bipolar Transistors ◽  
Integrated Circuit ◽  
High Speed ◽  
Room Temperature ◽  
Strain Relaxation ◽  
Bipolar Transistors ◽  
Sige Hbt ◽  
Integrated Circuit Manufacturing ◽  
Microstructural Behavior

SiGe is being extensively investigated for use in heterojunction bipolar-transistors (HBT) and high-speed integrated circuits. The material offers adjustable bandgaps, improved carrier mobilities over Si homostructures, and compatibility with Si-based integrated-circuit manufacturing. SiGe HBT performance can be improved by increasing the base-doping or by widening the base link-region by ion implantation. A problem that arises however is that implantation can enhance strain-relaxation of SiGe/Si.Furthermore, once misfit or threading dislocations result, the defects can give rise to recombination-generation in depletion regions of semiconductor devices. It is of relevance therefore to study the damage and anneal behavior of implanted SiGe layers. The present study investigates the microstructural behavior of phosphorus implanted pseudomorphic metastable Si0.88Ge0.12 films on silicon, exposed to various anneals.Metastable pseudomorphic Si0.88Ge0.12 films were grown ~265 nm thick on a silicon wafer by molecular-beam epitaxy. Pieces of this wafer were then implanted at room temperature with 100 keV phosphorus ions to a dose of 1.5×1015 cm-2.

Multiple phase transitions investigated by high-speed TEM

1990 ◽  
Vol 48 (4) ◽  
pp. 550-551
Author(s):  
Oleg Bostanjoglo ◽  
Peter Thomsen-Schmidt
Keyword(s):  
Phase Transitions ◽  
High Speed ◽  
Short Exposure ◽  
Semiconductor Film ◽  
Time Resolved ◽  
Short Exposure Time ◽  
Multiple Phase ◽  
Model Substance ◽  
History Of ◽  
Electron Image

Thin GexTe1-x (x = 0.15-0.8) were studied as a model substance of a composite semiconductor film, in addition being of interest for optical storage material. Two complementary modes of time-resolved TEM were used to trace the phase transitions, induced by an attached Q-switched (50 ns FWHM) and frequency doubled (532 nm) Nd:YAG laser. The laser radiation was focused onto the specimen within the TEM to a 20 μm spot (FWHM). Discrete intermediate states were visualized by short-exposure time doubleframe imaging /1,2/. The full history of a transformation was gained by tracking the electron image intensity with photomultiplier and storage oscilloscopes (space/time resolution 100 nm/3 ns) /3/. In order to avoid radiation damage by the probing electron beam to detector and specimen, the beam is pulsed in this continuous mode of time-resolved TEM,too.Short events ( <2 μs) are followed by illuminating with an extended single electron pulse (fig. 1c)

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