scholarly journals Exciton control in a room temperature bulk semiconductor with coherent strain pulses

2019 ◽  
Vol 5 (11) ◽  
pp. eaax2937 ◽  
Author(s):  
Edoardo Baldini ◽  
Adriel Dominguez ◽  
Tania Palmieri ◽  
Oliviero Cannelli ◽  
Angel Rubio ◽  
...  
Keyword(s):  
Room Temperature ◽  
Stark Effect ◽  
Crystalline Form ◽  
Deformation Potential ◽  
Phonon Interaction ◽  
Optical Stark Effect ◽  
Low Dimensional ◽  
Low Dimensional Materials ◽  
Coherent Acoustic Phonons ◽  
Bulk Semiconductor

Controlling the excitonic optical properties of room temperature semiconductors using time-dependent perturbations is key to future optoelectronic applications. The optical Stark effect in bulk and low-dimensional materials has recently shown exciton shifts below 20 meV. Here, we demonstrate dynamical tuning of the exciton properties by photoinduced coherent acoustic phonons in the cheap and abundant wide-gap semiconductor anatase titanium dioxide (TiO2) in single crystalline form. The giant coupling between the excitons and the photoinduced strain pulses yields a room temperature exciton shift of 30 to 50 meV and a marked modulation of its oscillator strength. An advanced ab initio treatment of the exciton-phonon interaction fully accounts for these results, and shows that the deformation potential coupling underlies the generation and detection of the giant acoustic phonon modulations.

Growth and Characterization of 1D Bi2Te3 Nanowires

2005 ◽  
Vol 886 ◽  
Author(s):  
M. Craps ◽  
Nick Gothard ◽  
Rahul Rao ◽  
Jian He ◽  
JoAn Hudson ◽  
...  
Keyword(s):  
Figure Of Merit ◽  
Room Temperature ◽  
Iron Catalyst ◽  
Inert Atmosphere ◽  
Laser Vaporization ◽  
Theoretical Studies ◽  
Low Dimensional ◽  
Quartz Substrates ◽  
Low Dimensional Materials

ABSTRACTBulk bismuth telluride (Bi2Te3) is one of the best known thermoelectric materials with a figure of merit ZT ∼1 at room temperature. Theoretical studies have suggested that low-dimensional materials may exhibit ZT values that exceed 1. In this study, we used the pulsed laser vaporization (PLV) method to prepare Bi2Te3 nanowires on silicon and quartz substrates by ablating Bi2Te3 targets in an inert atmosphere. Nano-sized gold or iron catalyst particles were used to seed the growth of the Bi2Te3 nanowires. Results from electron microscopy and Raman spectroscopy are discussed.

Ultralow-voltage all-carbon low-dimensional-material flexible transistors integrated by room-temperature photolithography incorporated filtration

Nanoscale ◽  
2019 ◽  
Vol 11 (32) ◽  
pp. 15029-15036 ◽  
Author(s):  
Chunhui Du ◽  
Min Zhang ◽  
Qiuyue Huang ◽  
Shengdong Zhang ◽  
Yang Chai
Keyword(s):  
Room Temperature ◽  
World Wide ◽  
Wearable Electronics ◽  
Flexible Devices ◽  
Low Dimensional ◽  
Low Dimensional Materials

Low dimensional materials (LDMs) have drawn world-wide attention as potential candidates applied in flexible and wearable electronics. However, integrating all-LDMs to realize independent-operation flexible devices are pretty challenging.

scholarly journals Tunable room-temperature spin-selective optical Stark effect in solution-processed layered halide perovskites

2016 ◽  
Vol 2 (6) ◽  
pp. e1600477 ◽  
Author(s):  
David Giovanni ◽  
Wee Kiang Chong ◽  
Herlina Arianita Dewi ◽  
Krishnamoorthy Thirumal ◽  
Ishita Neogi ◽  
...  
Keyword(s):  
Quantum Wells ◽  
Room Temperature ◽  
Stark Effect ◽  
Cryogenic Cooling ◽  
Oscillator Strengths ◽  
Multiple Quantum ◽  
Solution Processed ◽  
Lattice Matching ◽  
Light Matter Interaction ◽  
Optical Stark Effect

Ultrafast spin manipulation for opto–spin logic applications requires material systems that have strong spin-selective light-matter interaction. Conventional inorganic semiconductor nanostructures [for example, epitaxial II to VI quantum dots and III to V multiple quantum wells (MQWs)] are considered forerunners but encounter challenges such as lattice matching and cryogenic cooling requirements. Two-dimensional halide perovskite semiconductors, combining intrinsic tunable MQW structures and large oscillator strengths with facile solution processability, can offer breakthroughs in this area. We demonstrate novel room-temperature, strong ultrafast spin-selective optical Stark effect in solution-processed (C6H4FC2H4NH3)2PbI4 perovskite thin films. Exciton spin states are selectively tuned by ~6.3 meV using circularly polarized optical pulses without any external photonic cavity (that is, corresponding to a Rabi energy of ~55 meV and equivalent to applying a 70 T magnetic field), which is much larger than any conventional system. The facile halide and organic replacement in these perovskites affords control of the dielectric confinement and thus presents a straightforward strategy for tuning light-matter coupling strength.

Recent progress of intrinsic and stimulated room-temperature gas sensors enabled by low-dimensional materials

2021 ◽  
Author(s):  
Yinfen Cheng ◽  
Baiyu Ren ◽  
Kai Xu ◽  
Itthipon Jeerapan ◽  
Hui Chen ◽  
...  
Keyword(s):  
Control Systems ◽  
Gas Sensors ◽  
Room Temperature ◽  
Recent Progress ◽  
The Internet ◽  
Iot Platforms ◽  
Automation Control ◽  
Low Dimensional ◽  
Low Dimensional Materials ◽  
The Internet Of Things

Room-temperature (RT) gas sensors based on low-dimensional materials have rapidly received wide attention in various automation control systems and particularly in the Internet of Things (IoT) platforms due to their...

scholarly journals Resonant optical Stark effect in monolayer WS2

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Paul D. Cunningham ◽  
Aubrey T. Hanbicki ◽  
Thomas L. Reinecke ◽  
Kathleen M. McCreary ◽  
Berend T. Jonker
Keyword(s):  
Stark Effect ◽  
Transition Metal Dichalcogenides ◽  
Blue Shift ◽  
Coulomb Interactions ◽  
Many Body ◽  
Strong Light ◽  
Metal Dichalcogenides ◽  
Optical Stark Effect ◽  
Superposition States ◽  
Low Dimensional

AbstractBreaking the valley degeneracy in monolayer transition metal dichalcogenides through the valley-selective optical Stark effect (OSE) can be exploited for classical and quantum valleytronic operations such as coherent manipulation of valley superposition states. The strong light-matter interactions responsible for the OSE have historically been described by a two-level dressed-atom model, which assumes noninteracting particles. Here we experimentally show that this model, which works well in semiconductors far from resonance, does not apply for excitation near the exciton resonance in monolayer WS2. Instead, we show that an excitonic model of the OSE, which includes many-body Coulomb interactions, is required. We confirm the prediction from this theory that many-body effects between virtual excitons produce a dominant blue-shift for photoexcitation detuned from resonance by less than the exciton binding energy. As such, we suggest that our findings are general to low-dimensional semiconductors that support bound excitons and other many-body Coulomb interactions.

Room-Temperature Anomalous Coherent Excitonic Optical Stark Effect in Metal Halide Perovskite Quantum Dots

Nano Letters ◽  
2022 ◽  
Author(s):  
Megha Shrivastava ◽  
Franziska Krieg ◽  
Dipendranath Mandal ◽  
Ajay K. Poonia ◽  
Santu K. Bera ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Room Temperature ◽  
Stark Effect ◽  
Metal Halide ◽  
Metal Halide Perovskite ◽  
Perovskite Quantum Dots ◽  
Optical Stark Effect ◽  
Halide Perovskite

Symmetry and twins in the monophosphate tungsten bronze series (PO2)4(WO3)2m (2 ≤ m ≤ 14)

2000 ◽  
Vol 56 (3) ◽  
pp. 377-391 ◽  
Author(s):  
Pascal Roussel ◽  
Philippe Labbé ◽  
Daniel Groult
Keyword(s):  
Charge Density Wave ◽  
Room Temperature ◽  
Density Wave ◽  
Tungsten Bronze ◽  
Metallic State ◽  
Temperature Form ◽  
Low Dimensional ◽  
Low Dimensional Materials ◽  
High Temperature Form ◽  
M 14

Monophosphate tungsten bronze with pentagonal tunnels (PO2)4(WO3)2 m are low-dimensional materials with charge density wave (CDW)-type electron instabilities. Two forms of the structure can thus be expected for all the members of the series: a low-temperature form (LT) corresponding to the CDW state and a high-temperature form (HT) corresponding to a normal metallic state. The HT form is described here for m = 9 and compared with that of the m = 5 and m = 7 counterparts. It is shown that a systematic twin phenomenon must be taken into account for HT members because of two possible configurations of the tilting mode of WO6 octahedra. The structure is also compared with that of m = 10, which exhibits the modulated CDW–LT form at room temperature. Owing to two possible polarization directions of the segments built of m WO6 octahedra, a twin phenomenon is also encountered in the LT forms. A review of all the structures known at present (m = 2, 4, 5, 6, 7, 8, 9, 10, 12) leads us to propose a structural law based on the building mode of WO6 octahedra in WO3-type slabs to explain the symmetry changes observed between even and odd members of the series.

scholarly journals The Highly Uniform Photoresponsivity from Visible to Near IR Light in Sb2Te3 Flakes

Sensors ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 1535
Author(s):  
Shiu-Ming Huang ◽  
Jai-Lung Hung ◽  
Mitch Chou ◽  
Chi-Yang Chen ◽  
Fang-Chen Liu ◽  
...  
Keyword(s):  
Band Structure ◽  
Energy Difference ◽  
Experimental Result ◽  
Light Illumination ◽  
Near Ir ◽  
State Band ◽  
Valence Bands ◽  
Low Dimensional ◽  
Low Dimensional Materials ◽  
Ir Light

Broadband photosensors have been widely studied in various kinds of materials. Experimental results have revealed strong wavelength-dependent photoresponses in all previous reports. This limits the potential application of broadband photosensors. Therefore, finding a wavelength-insensitive photosensor is imperative in this application. Photocurrent measurements were performed in Sb2Te3 flakes at various wavelengths ranging from visible to near IR light. The measured photocurrent change was insensitive to wavelengths from 300 to 1000 nm. The observed wavelength response deviation was lower than that in all previous reports. Our results show that the corresponding energies of these photocurrent peaks are consistent with the energy difference of the density of state peaks between conduction and valence bands. This suggests that the observed photocurrent originates from these band structure peak transitions under light illumination. Contrary to the most common explanation that observed broadband photocurrent carrier is mainly from the surface state in low-dimensional materials, our experimental result suggests that bulk state band structure is the main source of the observed photocurrent and dominates the broadband photocurrent.

scholarly journals Transforming Pt-SnO2 Nanoparticles into Pt-SnO2 Composite Nanoceramics for Room-Temperature Hydrogen-Sensing Applications

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2123
Author(s):  
Ming Liu ◽  
Caochuang Wang ◽  
Pengcheng Li ◽  
Liang Cheng ◽  
Yongming Hu ◽  
...  
Keyword(s):  
Room Temperature ◽  
Gas Sensing ◽  
Sintering Temperature ◽  
Sno2 Nanoparticles ◽  
Hydrogen Sensing ◽  
Sensing Applications ◽  
Nanostructured Metal Oxides ◽  
Low Dimensional ◽  
Sensing Characteristics ◽  
Nanostructured Metal

Many low-dimensional nanostructured metal oxides (MOXs) with impressive room-temperature gas-sensing characteristics have been synthesized, yet transforming them into relatively robust bulk materials has been quite neglected. Pt-decorated SnO2 nanoparticles with 0.25–2.5 wt% Pt were prepared, and highly attractive room-temperature hydrogen-sensing characteristics were observed for them all through pressing them into pellets. Some pressed pellets were further sintered over a wide temperature range of 600–1200 °C. Though the room-temperature hydrogen-sensing characteristics were greatly degraded in many samples after sintering, those samples with 0.25 wt% Pt and sintered at 800 °C exhibited impressive room-temperature hydrogen-sensing characteristics comparable to those of their counterparts of as-pressed pellets. The variation of room-temperature hydrogen-sensing characteristics among the samples was explained by the facts that the connectivity between SnO2 grains increases with increasing sintering temperature, and Pt promotes oxidation of SnO2 at high temperatures. These results clearly demonstrate that some low-dimensional MOX nanocrystals can be successfully transformed into bulk MOXs with improved robustness and comparable room-temperature gas-sensing characteristics.

scholarly journals Definition of a scoring parameter to identify low-dimensional materials components

2019 ◽  
Vol 3 (3) ◽  
Author(s):  
Peter Mahler Larsen ◽  
Mohnish Pandey ◽  
Mikkel Strange ◽  
Karsten Wedel Jacobsen
Keyword(s):  
Definition Of ◽  
Low Dimensional ◽  
Low Dimensional Materials
Sign in / Sign up

Export Citation Format

Share Document