Investigation on Relationship between Charge Transfer Position and Dielectric Definition of Average Energy Gap in Eu3+-Doped Compounds

2007 ◽  
Vol 111 (7) ◽  
pp. 3205-3210 ◽  
Author(s):  
Ling Li ◽  
Shihong Zhou ◽  
Siyuan Zhang
Keyword(s):  
Charge Transfer ◽  
Energy Gap ◽  
Average Energy ◽  
Definition Of

Effective Adsorption of a-series Chemical Warfare Agents on Graphdiyne Nanoflake; A DFT Study

2021 ◽  
Author(s):  
Hasnain Sajid ◽  
Sidra Khan ◽  
Khurshid Ayub ◽  
Tariq Mahmood
Keyword(s):  
Charge Transfer ◽  
Density Functional ◽  
Energy Gap ◽  
Average Energy ◽  
Chemical Warfare Agents ◽  
Chemical Warfare ◽  
Sensor Material ◽  
Adsorption Affinity ◽  
Warfare Agents ◽  
Adsorption Energies

Abstract Chemical warfare agents (CWAs) are highly poisonous and their presence may cause diverse effect not only on living organisms but on environment as well. Therefore, their detection and removal in a short time span is very important. In this regard, here the utility of graphdiyne (GDY) nanoflake is studied theoretically as an electrochemical sensor material for the hazardous CWAs including A-230, A-232, A-234. Herein, we explain the phenomenon of adsorption of A-series CWAs on GDY nanoflake within the density functional theory (DFT) framework. The characterization of adsorption is based on optimized geometries, BSSE corrected energies, SAPT, RDG, FMO, CHELPG charge transfer, QTAIM and UV-Vis analyses. The calculated counterpoise adsorption energies for reported complexes range from -13.70 to -17.19 kcal mol-1. These adsorption energies show that analytes are physiosorbed onto GDY which usually takes place through noncovalent interactions. The noncovalent adsorption of CWAs on GDY is also attributed by the SAPT0, RDG and QTAIM analyses. These properties also reveal that dispersion factors dominate in the complexes among many noncovalent components (exchange, induction, electrostatic, steric repulsion). In order the estimate the sensitivity of GDY, the %sensitivity and average energy gap variations are quantitatively measured by energies of HOMO and LUMO orbitals. In term of adsorption affinity of GDY, UV-Vis analysis, CHELPG charge transfer and DOS analysis depict an appreciable response towards these toxic CWAs.

Charge-Transfer Dipoles at the Si-SiO2 Interface and the Metal-Semiconductor Worfunction Difference In Mos Devices.

1987 ◽  
Vol 105 ◽  
Author(s):  
Hisham Z. Massoud
Keyword(s):  
Dipole Moment ◽  
Charge Transfer ◽  
Dipole Moments ◽  
Silicon Substrates ◽  
Interface Dipole ◽  
Mos Devices ◽  
Flatband Voltage ◽  
The Difference ◽  
Definition Of ◽  
Mos Structures

AbstractThe magnitude of the dipole moment at the Si-SiO2 interface resulting from partial charge transfer that takes place upon the formation of interface bonds has been calculated. The charge transfer occurs because of the difference in electronegativity between silicon atoms and SiO2 molecules which are present across the interface. Results obtained for (100) and (111) silicon substrates indicate that the magnitude of the interface dipole moment is dependent on substrate orientation and the interface chemistry. Dipole moments at the Si-SiO2 and gate-SiO2 interfaces should be included in the definition of the flatband voltage VFB of MOS structures. CV-based measurements of the metal-semiconductor workfunction difference φms on (100) and (111) silicon oxidized in dry oxygen and metallized with Al agree with the predictions of this model. Other types of interface dipoles and their processing dependence are briefly discussed.

scholarly journals Empirical Relation for Electronic and Optical Properties of Binary Tetrahedral Semiconductors

2021 ◽  
Keyword(s):  
Dielectric Constant ◽  
Optical Properties ◽  
Atomic Number ◽  
Energy Gap ◽  
Empirical Relation ◽  
Average Energy ◽  
Optical Parameters ◽  
Dielectric Analysis ◽  
Average Atomic Number ◽  
Tetrahedral Semiconductors

The concept of ionicity has been developed by Phillips and Van Vechten from the dielectric analysis of the semiconductors and insulators to evaluate various bond parameters of binary tetrahedral (AIIBVI and AIIIBV) semiconductors. In this paper, an advance hypothesis of average atomic number of the elements in a compound has been used to evaluate intrinsic electronic and optical parameters such as ionic gap (Ec), average energy gap (Eg), crystal ionicity (fi) and dielectric constant (ϵ) of binary tetrahedral semiconductors.

ELECTRONIC, OPTICAL AND MECHANICAL PROPERTIES OF AIIBVI SEMICONDUCTORS

2012 ◽  
Vol 26 (08) ◽  
pp. 1250020 ◽  
Author(s):  
DHEERENDRA SINGH YADAV ◽  
A. S. VERMA
Keyword(s):  
Experimental Data ◽  
Mechanical Properties ◽  
Energy Gap ◽  
Average Energy ◽  
Compound Semiconductors ◽  
Electronic Polarizability ◽  
Zinc Blende ◽  
Energy Gaps ◽  
Optical And Mechanical Properties ◽  
Good Agreement

The modified dielectric theory of solids is applied to investigate electronic, optical and mechanical properties of A II B VI binary semiconductors ( ZnO, ZnS, ZnSe, ZnTe, CdO, CdS, CdSe, CdTe, HgS, HgSe & HgTe ). The values of homopolar gaps (Eh), heteropolar gaps (Ec) and average energy gaps (Eg) were evaluated for these A II B VI groups of binary semiconductors with Zinc-blende (ZB) structure. The derived values of average energy gap (Eg) were found to be in excellent agreement with the values obtained from the Penn model except ZnO . The electronic polarizability was investigated using Chemla's relation and the values were found to be in a very good agreement with the results obtained from the Clausius–Mossotti relation. The crystal ionicity (fi) was evaluated and the obtained values were compared with the values obtained by different researchers. The evaluated values of crystal ionicity were used to calculate the electronic, optical, mechanical properties such as bulk modulus (B in GPa) cohesive energy or total energy (U in Ryd. electron) and microhardness (H in GPa) of these compound semiconductors. A good agreement has been found between calculated and experimental data.

Closure of the charge-transfer energy gap and metallization ofNiI2under pressure

1993 ◽  
Vol 71 (24) ◽  
pp. 4011-4014 ◽  
Author(s):  
Anthony L. Chen ◽  
Peter Y. Yu ◽  
R. Dean Taylor
Keyword(s):  
Charge Transfer ◽  
Energy Gap ◽  
Transfer Energy ◽  
Charge Transfer Energy

Temperature-Dependent Energy Gap Shift and Thermally Activated Transition in Multilayer CdTe/ZnTe Quantum Dots

2015 ◽  
Vol 15 (10) ◽  
pp. 8120-8124
Author(s):  
Minh Tan Man ◽  
Hong Seok Lee
Keyword(s):  
Quantum Dots ◽  
Energy Gap ◽  
Average Energy ◽  
Growth Conditions ◽  
Carrier Dynamics ◽  
Phonon Coupling ◽  
Temperature Quenching ◽  
Temperature Dependent ◽  
Thermally Activated ◽  
Best Fit

We investigated the influence of growth conditions on carrier dynamics in multilayer CdTe/ZnTe quantum dots (QDs) by monitoring the temperature dependence of the photoluminescence emission energy. The results were analyzed using the empirical Varshni and O’Donnell relations for temperature variation of the energy gap shift. Best fit values showed that the thermally activated transition between two different states occurs due to band low-temperature quenching with values separated by 5.0–6.5 meV. The addition of stack periods in multilayer CdTe/ZnTe QDs plays an important role in the energy gap shift, where the exciton binding energy is enhanced, and, conversely, the exciton-phonon coupling strength is suppressed with an average energy of 19.3–19.8 meV.

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