scholarly journals Temperature dependent radiative and non-radiative recombination dynamics in CdSe–CdTe and CdTe–CdSe type II hetero nanoplatelets

2016 ◽  
Vol 18 (4) ◽  
pp. 3197-3203 ◽  
Author(s):  
Riccardo Scott ◽  
Sebastian Kickhöfel ◽  
Oliver Schoeps ◽  
Artsiom Antanovich ◽  
Anatol Prudnikau ◽  
...  
Keyword(s):  
Temperature Dependence ◽  
Radiative Recombination ◽  
Type Ii ◽  
Temperature Dependent ◽  
Radiative Lifetimes ◽  
First Time ◽  
Recombination Dynamics

We reveal for the first time the temperature dependence of the radiative and non-radiative lifetimes of type II excitons in hetero nanoplatelets.

Temperature-dependent halogen⋯halogen synthon crossover in coordination compounds

CrystEngComm ◽  
2014 ◽  
Vol 16 (36) ◽  
pp. 8479-8485 ◽  
Author(s):  
Hamid Reza Khavasi ◽  
Maryam Esmaeili
Keyword(s):  
Coordination Compounds ◽  
Type I ◽  
Type Ii ◽  
Temperature Dependent ◽  
First Time

The crossover between type I and type II Br⋯Br synthons on the formation of coordination compounds has been investigated for the first time.

scholarly journals Volumetric Properties for the Aqueous Solution of Yttrium Trichloride at Temperatures from 283.15 to 363.15 K and Ambient Pressure

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Zhenzhen Jiang ◽  
Chi Ma ◽  
Gaoling Liu ◽  
Kangrui Sun ◽  
Mingli Li ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Temperature Dependence ◽  
Binary Systems ◽  
Coefficient Of Thermal Expansion ◽  
Ambient Pressure ◽  
Interaction Model ◽  
Volumetric Properties ◽  
Temperature Dependent ◽  
Geothermal Waters ◽  
First Time

To effectively develop the rare earth elements resources from the geothermal waters, it is essential to understand the volumetric properties of the aqueous solution system to establish the relative thermodynamic model. In this study, densities of YCl3 (aq) at the molalities of 0.08837–1.60639 mol·kg−1 from 283.15 K to 363.15 K at 5 K intervals and ambient pressure were measured experimentally by an Anton Paar digital vibrating-tube densimeter. Based on experimental data, the volumetric properties including apparent molar volume (Vϕ) and the coefficient of thermal expansion of the solution (α) of the binary systems (YCl3 + H2O) were derived. The 3D diagram (mi, T, Vϕ) of apparent molar volumes against temperature and molality was plotted. On the basis of the Pitzer ion-interaction model of electrolyte, the Pitzer single-salt parameters ( β MX 0 v , β MX 1 v , and C MX v ) for YCl3 and temperature-dependence equation F(i, p, T) = a1 + a2ln(T/298.15) + a3(T-298.15) + a4/(620-T) + a5(T-227) as well as their coefficients ai (i = 1–5) in the binary system were obtained for the first time. The values of Pitzer single-salt parameters of YCl3 agree well with the calculated values corresponding to the temperature-dependence equations, indicating that single-salt parameters and temperature-dependent formula obtained in this work are reliable.

19F Nuclear Quadrupole Coupling in some Halomethanes

1986 ◽  
Vol 41 (1-2) ◽  
pp. 171-174 ◽  
Author(s):  
M. Frank ◽  
F. Gubitz ◽  
W. Ittner ◽  
W. Kreische ◽  
A. Labahn ◽  
...  
Keyword(s):  
Angular Distribution ◽  
Simple Model ◽  
Temperature Dependence ◽  
Coupling Constants ◽  
Temperature Dependent ◽  
Distribution Method ◽  
Quadrupole Coupling ◽  
Time Differential ◽  
Nuclear Quadrupole

The 19F quadrupole coupling constants in CF4, CHF3, CClF3 and CHClF2 are reported. The measurements were carried out temperature dependent using the time differential perturbed angular distribution method (TDPAD). The temperature dependence can be satisfactorily described in the framework of the Bayer-Kushida theory. A simple model is used to explain the appearance of H-F and Cl-F coupling constants in CHF3/CHClF2 and CClF3, respectively.

Ionized AGN outflows are less powerful than assumed: A multi-wavelength census of outflows in type II AGN

2019 ◽  
Vol 15 (S356) ◽  
pp. 225-225
Author(s):  
Dalya Baron
Keyword(s):  
Optical Emission ◽  
Infrared Emission ◽  
Type Ii ◽  
Ionized Gas ◽  
Kinetic Coupling ◽  
Mass Outflow ◽  
Multi Wavelength ◽  
Novel Method ◽  
First Time ◽  
Ionization Parameter

AbstractIn this talk I will show that multi-wavelength observations can provide novel constraints on the properties of ionized gas outflows in AGN. I will present evidence that the infrared emission in active galaxies includes a contribution from dust which is mixed with the outflow and is heated by the AGN. We detect this infrared component in thousands of AGN for the first time, and use it to constrain the outflow location. By combining this with optical emission lines, we constrain the mass outflow rates and energetics in a sample of 234 type II AGN, the largest such sample to date. The key ingredient of our new outflow measurements is a novel method to estimate the electron density using the ionization parameter and location of the flow. The inferred electron densities, ∼104.5 cm−3, are two orders of magnitude larger than found in most other cases of ionized outflows. We argue that the discrepancy is due to the fact that the commonly-used [SII]-based method underestimates the true density by a large factor. As a result, the inferred mass outflow rates and kinetic coupling efficiencies are 1–2 orders of magnitude lower than previous estimates, and 3–4 orders of magnitude lower than the typical requirement in hydrodynamic cosmological simulations. These results have significant implications for the relative importance of ionized outflows feedback in this population.

scholarly journals Temperature-Dependent Photoluminescence of ZnO Thin Films Grown on Off-Axis SiC Substrates by APMOCVD

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 1035
Author(s):  
Ivan Shtepliuk ◽  
Volodymyr Khranovskyy ◽  
Arsenii Ievtushenko ◽  
Rositsa Yakimova
Keyword(s):  
Optical Properties ◽  
Structural Quality ◽  
Organic Chemical ◽  
Zno Films ◽  
Vicinal Surfaces ◽  
Temperature Dependent ◽  
Step Flow ◽  
Step Flow Growth ◽  
First Time ◽  
Temperature Dependent Photoluminescence

The growth of high-quality ZnO layers with optical properties congruent to those of bulk ZnO is still a great challenge. Here, for the first time, we systematically study the morphology and optical properties of ZnO layers grown on SiC substrates with off-cut angles ranging from 0° to 8° by using the atmospheric pressure meta–organic chemical vapor deposition (APMOCVD) technique. Morphology analysis revealed that the formation of the ZnO films on vicinal surfaces with small off-axis angles (1.4°–3.5°) follows the mixed growth mode: from one side, ZnO nucleation still occurs on wide (0001) terraces, but from another side, step-flow growth becomes more apparent with the off-cut angle increasing. We show for the first time that the off-cut angle of 8° provides conditions for step-flow growth of ZnO, resulting in highly improved growth morphology, respectively structural quality. Temperature-dependent photoluminescence (PL) measurements showed a strong dependence of the excitonic emission on the off-cut angle. The dependences of peak parameters for bound exciton and free exciton emissions on temperature were analyzed. The present results provide a correlation between the structural and optical properties of ZnO on vicinal surfaces and can be utilized for controllable ZnO heteroepitaxy on SiC toward device-quality ZnO epitaxial layers with potential applications in nano-optoelectronics.

Electronic Properties of Bismuth Nanowires

2001 ◽  
Vol 679 ◽  
Author(s):  
Stephen B. Cronin ◽  
Yu-Ming Lin ◽  
Oded Rabin ◽  
Marcie R. Black ◽  
Gene Dresselhaus ◽  
...  
Keyword(s):  
Theoretical Model ◽  
Band Structure ◽  
Temperature Dependence ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Temperature Dependent ◽  
Si Substrates ◽  
Bismuth Nanowires ◽  
Bi Nanowire ◽  
Anodic Alumina Templates

ABSTRACTThe pressure filling of anodic alumina templates with molten bismuth has been used to synthesize single crystalline bismuth nanowires with diameters ranging from 7 to 200nm and lengths of 50μm. The nanowires are separated by dissolving the template, and electrodes are affixed to single Bi nanowires on Si substrates. A focused ion beam (FIB) technique is used first to sputter off the oxide from the nanowires with a Ga ion beam and then to deposit Pt without breaking vacuum. The resistivity of a 200nm diameter Bi nanowire is found to be only slightly greater than the bulk value, while preliminary measurements indicate that the resistivity of a 100nm diameter nanowire is significantly larger than bulk. The temperature dependence of the resistivity of a 100nm nanowire is modeled by considering the temperature dependent band parameters and the quantized band structure of the nanowires. This theoretical model is consistent with the experimental results.

Temperature Dependence of the Intervalley Deformation Potential of GaAs/AlAs Superlattices Under Hydrostatic Pressure

1997 ◽  
Vol 499 ◽  
Author(s):  
S. Guha ◽  
Q. Cai ◽  
M. Chandrasekhar ◽  
H. R. Chandrasekhar ◽  
Hyunjung Kim ◽  
...  
Keyword(s):  
Hydrostatic Pressure ◽  
Temperature Dependence ◽  
Pressure Dependence ◽  
Type I ◽  
Type Ii ◽  
Deformation Potential ◽  
Intervalley Scattering

ABSTRACTWe have studied the pressure dependence of the type-I and type-II transitions in (GaAs)m/(AlAs)m superlattices by photoluminescence (PL) spectroscopy. From the study of PL linewidths of the type-I exciton as a function of pressure and temperature, we determine the intervalley deformation potential. Beyond the type-I and type-II crossover, the PL linewidth increases both as a function of pressure and temperature. We find that the electron-phonon deformation potential for Γ-X intervalley scattering varies with temperature.

Evidence for Dark States in the Temperature Dependent Recombination Dynamics of InGaN/GaN Quantum Wells

2013 ◽  
Vol 52 (8S) ◽  
pp. 08JL12
Author(s):  
Tom J. Badcock ◽  
Phil Dawson ◽  
Rachel A. Oliver ◽  
Menno J. Kappers ◽  
Colin J. Humphreys
Keyword(s):  
Quantum Wells ◽  
Temperature Dependent ◽  
Recombination Dynamics
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