scholarly journals Two-dimensional hybrid perovskites sustaining strong polariton interactions at room temperature

2019 ◽  
Vol 5 (5) ◽  
pp. eaav9967 ◽  
Author(s):  
A. Fieramosca ◽  
L. Polimeno ◽  
V. Ardizzone ◽  
L. De Marco ◽  
M. Pugliese ◽  
...  
Keyword(s):  
Quantum Wells ◽  
Degrees Of Freedom ◽  
Room Temperature ◽  
Optical Cavity ◽  
Oscillator Strengths ◽  
Layered Perovskite ◽  
Two Dimensional ◽  
Coherent Coupling ◽  
Highly Nonlinear ◽  
Order Of Magnitude

Polaritonic devices exploit the coherent coupling between excitonic and photonic degrees of freedom to perform highly nonlinear operations with low input powers. Most of the current results exploit excitons in epitaxially grown quantum wells and require low-temperature operation, while viable alternatives have yet to be found at room temperature. We show that large single-crystal flakes of two-dimensional layered perovskite are able to sustain strong polariton nonlinearities at room temperature without the need to be embedded in an optical cavity formed by highly reflecting mirrors. In particular, exciton-exciton interaction energies are shown to be spin dependent, remarkably similar to the ones known for inorganic quantum wells at cryogenic temperatures, and more than one order of magnitude larger than alternative room temperature polariton devices reported so far. Because of their easy fabrication, large dipolar oscillator strengths, and strong nonlinearities, these materials pave the way for realization of polariton devices at room temperature.

VLS Growth of Position-controlled InP Nanowires and Formation of Radial Heterostructures on Mask-patterned InP Substrates

2014 ◽  
Vol 1659 ◽  
pp. 181-186 ◽  
Author(s):  
Kenichi Kawaguchi ◽  
Hisao Sudo ◽  
Manabu Matsuda ◽  
Mitsuru Ekawa ◽  
Tsuyoshi Yamamoto ◽  
...  
Keyword(s):  
Quantum Wells ◽  
Room Temperature ◽  
Wavelength Region ◽  
Two Dimensional ◽  
Au Catalyst ◽  
Vapor Liquid Solid ◽  
Vls Growth ◽  
Hcl Gas ◽  
Inp Substrates ◽  
Anomalous Growth

ABSTRACTPosition-controlled InP nanowires (NWs) with separations of 10-100 μm were grown by the vapor-liquid-solid (VLS) method using Au-deposited SiO2-mask-patterned InP substrates. Excess indium species diffused from the large mask region formed plural tilted NW-like structures from single openings in addition to the vertical VLS NWs formed by Au catalyst. The introduction of HCl gas during the NW growth was found to efficiently suppress the tilted NW-like structures. Vertical InP NWs without anomalous growth were successfully formed by controlling the HCl flow rate. Moreover, single InP/InAsP/InP quantum wells (QWs) with wurtzite crystal phase structure were epitaxially grown on the sidewall of the position-controlled InP NWs, and two-dimensional arrayed patterns of photoluminescence (PL) coming from the radial QWs were clearly observed in the 1.3-μm wavelength region at room temperature.

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.

scholarly journals Strong exciton–photon coupling at room temperature in microcavities containing two-dimensional layered perovskite compounds

2008 ◽  
Vol 10 (6) ◽  
pp. 065007 ◽  
Author(s):  
G Lanty ◽  
A Bréhier ◽  
R Parashkov ◽  
J S Lauret ◽  
E Deleporte
Keyword(s):  
Room Temperature ◽  
Layered Perovskite ◽  
Two Dimensional ◽  
Photon Coupling

Distinguishing Energy- and Charge-Transfer Processes in Layered Perovskite Quantum Wells with Two-Dimensional Action Spectroscopies

2020 ◽  
Vol 11 (12) ◽  
pp. 4570-4577 ◽  
Author(s):  
Ninghao Zhou ◽  
Zhenyu Ouyang ◽  
Jun Hu ◽  
Olivia F. Williams ◽  
Liang Yan ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Quantum Wells ◽  
Layered Perovskite ◽  
Two Dimensional ◽  
Transfer Processes

Enhancing the photoluminescence response from thick Ge-on-Si layers using the photonic crystals

2021 ◽  
Author(s):  
Dmitry V Yurasov ◽  
Artem N Yablonskiy ◽  
Natalya A Baidakova ◽  
Mikhail V Shaleev ◽  
Ekaterina E Rodyakina ◽  
...  
Keyword(s):  
Photonic Crystals ◽  
Room Temperature ◽  
Optically Active ◽  
Far Field ◽  
Two Dimensional ◽  
Wave Analysis ◽  
Room Temperature Photoluminescence ◽  
Order Of Magnitude ◽  
Spectroscopy Optical ◽  
Photoluminescence Response

Abstract More than an order of magnitude enhancement of the room-temperature photoluminescence (PL) signal from rather thick Ge layers grown on Si(001) was obtained by utilization of the two-dimensional photonic crystals (PhC). A set of PhCs with different periods and filling factors was fabricated and studied using a micro-PL spectroscopy. Optical features of the fabricated PhCs were also theoretically modeled using a rigorously coupled wave analysis which allowed to bring the observed peaks in the PL response into correlation with the different modes of PhC. In particular, we were able to associate the well-resolved peaks in the PL spectra with the optically active modes of the PhCs. The obtained results proved the possibility of using a homogeneously distributed active medium in PhCs without the formation of specially designed cavities in order to redistribute the internal emitted light into the required modes and efficiently extract it to the far field. The relative simplicity and higher tolerance to fabrication imperfections, as well as the large working area of such kind of PhCs as compared to PhCs with microcavities can be advantageous for creating a PhC-based Si-compatible light source for the telecom band.

Recombination Dynamics in Nitride Quantum Boxes and Quantum Wells for Colors Ranging from the UV to the Red

2000 ◽  
Vol 639 ◽  
Author(s):  
P. Lefebvre ◽  
A. Morel ◽  
M. Gallart ◽  
T. Taliercio ◽  
B. Gil ◽  
...  
Keyword(s):  
Quantum Well ◽  
Quantum Wells ◽  
Electric Fields ◽  
Room Temperature ◽  
Stokes Shift ◽  
Oscillator Strengths ◽  
Time Resolved ◽  
Transition Energies ◽  
Radiative Efficiency ◽  
Time Resolved Photoluminescence

ABSTRACTTime-resolved photoluminescence experiments at varying temperature are performed on a series of InxGa1−xN/GaN quantum well and quantum box samples of similar compositions (0.15 < x < 0.20). The results are analyzed by using envelope-function calculations of transition energies and oscillator strengths, accounting for internal electric fields. The respective influences of localization and electric fields on radiative and nonradiative lifetimes and on the Stokes shift are deduced. The results indicate that the spatial extension of localization centers is much smaller than the size of the quantum boxes (∼10 × 3 nm, typically). The room-temperature radiative efficiency of both quantum well and quantum box samples is enhanced by replacing the topmost GaN barrier by an AlGaN one.

scholarly journals Room temperature quantum spin Hall states in two-dimensional crystals composed of pentagonal rings and their quantum wells

2016 ◽  
Vol 8 (4) ◽  
pp. e264-e264 ◽  
Author(s):  
Yandong Ma ◽  
Liangzhi Kou ◽  
Xiao Li ◽  
Ying Dai ◽  
Thomas Heine
Keyword(s):  
Quantum Wells ◽  
Room Temperature ◽  
Quantum Spin ◽  
Two Dimensional ◽  
Hall States ◽  
Quantum Spin Hall

Luminescence Properties of Europium-Doped Yttrium Oxides Derived from Their Dodecylsulfate-Templated Mesostructure and Nanotube Forms

2003 ◽  
Vol 775 ◽  
Author(s):  
Tsuyoshi Kijima ◽  
Kenichi Iwanaga ◽  
Tomomi Hamasuna ◽  
Shinji Mohri ◽  
Mitsunori Yada ◽  
...  
Keyword(s):  
Room Temperature ◽  
Broad Band ◽  
Concentration Quenching ◽  
Precipitation Method ◽  
Homogeneous Precipitation ◽  
Bulk Materials ◽  
Main Band ◽  
Homogeneous Precipitation Method ◽  
Order Of Magnitude ◽  
Weak Luminescence

AbstractEuropium-doped hexagonal-mesostructured and nanotubular yttrium oxides templated by dodecylsulfate species as well as surfactant free bulk oxides were synthesized by the homogeneous precipitation method. All the as grown nanostructured or bulk materials with amorphous or poorly crystalline frameworks showed weak luminescence bands at room temperature. On calcination at 1000°C these materials were converted into highly crystalline yttrium oxides, resulting in a total increase in intensity of all the bands by one order of magnitude. In the hexagonal-mesostructured system, the main band due to the 5D0-7F2 transition for the calcined phases showed a sharp but asymmetrical multiplet splitting indicating multiple Eu sites. Concentration quenching was found at a Eu content of 3 mol% or above for these phases. In contrast, the main emission for the calcined solids in the nanotubular system occurred as poorly resolved broad band and the intensity of the main band at higher Eu content was significantly enhanced compared with those for the other two systems.

Temperature Dependence of the Self-Assembled Styrene Based Random Ionomers in Aqueous Solution

2003 ◽  
Vol 775 ◽  
Author(s):  
Sung-Hwa Oh ◽  
Ju-Myung Song ◽  
Joon-Seop Kim ◽  
Hyang-Rim Oh ◽  
Jeong-A Yu
Keyword(s):  
Partition Coefficients ◽  
Room Temperature ◽  
Aqueous Media ◽  
The Self ◽  
Spectroscopic Methods ◽  
Ion Content ◽  
Repeat Units ◽  
Notable Effect ◽  
Order Of Magnitude ◽  
Experimental Errors

AbstractSolution behaviors of poly(styrene-co-sodium methacrylate) were studied by fluorescence spectroscopic methods using pyrene as a probe. The mol% of methacrylate was in the range 3.6–9.4. Water and N,N-dimethylforamide(DMF) mixture was used as a solvent (DMF/water = 0.2 mol %). The critical micelle (or aggregation) concentrations of ionomers and the partition coefficients of pyrene were obtained the temperature range 10–80°C. At room temperature, the values of CMCs (or CACs) were in the range 4.7 ×10-6 5.3 ×10-6 g/mL and we could not find any notable effect of the content of ionic repeat units within the experimental errors. Unlike CMCs, as the ion content increased, partitioning of pyrene between the hydrophobic aggregates and an aqueous media decreased from 1.5 ×105 to 9.4 ×104. As the temperature increased from 10 to 80 °C, the values of CMCs increased less than one order of magnitude. While, the partition coefficients of pyrene decreased one order of magnitude and the effect of the ion content became negligible.

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