Study of Electronic Properties and UV-Vis Spectrum of a Single Molecule as Molecular Electronics

2021 ◽  
Vol 19 (10) ◽  
pp. 77-81
Author(s):  
Khalid Jabbar Mutashar ◽  
Jabir Shaker Hameed ◽  
Hamid Ibrahim Abbood
Keyword(s):  
Absorption Spectrum ◽  
Electronic Properties ◽  
Valence Band ◽  
Molecular Electronics ◽  
Conduction Band ◽  
Single Molecule ◽  
Energy Gap ◽  
Basis Sets ◽  
Direct Transition ◽  
Wide Range

Current study deals with electronic properties and absorption spectrum calculations for a single molecule. The calculations were done based on the theory of density function DF. Our result showed the large basis sets 6-31G (d, P) with functional B3LYP is a suitable using for the relaxation of the studied structure. We showed a single molecule has small value of energy gap; it takes place in a wide range of molecular electronics as semiconductor material. The molecule is a soft molecule and can an electron to be transfer easily from valence band to conduction band. A single molecule can be interacting with the surrounding species due to it is higher electrophilic index. There is no direct transition from valence to conduction for a single molecule, the transition is recorded from sublevel in valence band to conduction band.

scholarly journals Conduction Band Engineering of Half-Heusler Thermoelectrics Using Orbital Chemistry

2022 ◽  
Author(s):  
Shuping Guo ◽  
Shashwat Anand ◽  
Madison K. Brod ◽  
Yongsheng Zhang ◽  
G. Jeffrey Snyder
Keyword(s):  
Electronic Properties ◽  
Valence Band ◽  
Conduction Band ◽  
Thermoelectric Materials ◽  
Band Engineering

Semiconducting half-Heusler (HH, XYZ) phases are promising thermoelectric materials owing to their versatile electronic properties. Because the valence band of half-Heusler phases benefits from the valence band extrema at several...

The optical and electronic properties of semiconducting diamond

1993 ◽  
Vol 342 (1664) ◽  
pp. 233-244 ◽  
Keyword(s):  
Absorption Spectrum ◽  
Electronic Properties ◽  
Valence Band ◽  
Chemical Vapour ◽  
Impurity Band ◽  
Thermally Activated ◽  
Boron Doped ◽  
Optical And Electronic Properties ◽  
Temperature Dependences ◽  
Semiconducting Diamond

In this paper I review the evidence that shows that the optical and electronic properties of semiconducting diamond can be understood in terms of boron acceptors partially compensated by deep donors. In natural semiconducting diamond, in which the total impurity concentration is less than 1 ppm, there is a lot of fine structure in the acceptor absorption spectrum that is not fully understood, and the electrical conductivity is primarily associated with the thermally activated excitation of holes from the acceptor ground state to the valence band. Some of the problems regarding the analysis of Hall effect data in this material are discussed, including the temperature dependences of the scattering mechanisms, of the contribution from the split-off valence band and of the population of excited states. There are no adequate theoretical descriptions of any of these processes, and this leads to some uncertainties in the values of the parameters derived from the temperature dependence of the Hall coefficient. For boron-doped synthetic diamond, and thin film diamond grown by chemical vapour deposition (CVD), the defect concentrations are generally much higher, and much more inhomogeneous, than in natural semiconducting diamond. This results in a substantial broadening of the acceptor absorption spectrum and the electronic properties are greatly modified by increasing contributions from impurity band conduction as the acceptor concentrations are increased, leading to very low mobility values. For both poly crystalline and single crystal homoepitaxial CVD diamond, measurements of the electrical properties can be completely invalidated by the presence of a surface layer of non-diamond carbon.

Density of Deep Bandgap States in Amorphous Silicon From the Temperature Dependence of Thin Film Transistor Current

1994 ◽  
Vol 336 ◽  
Author(s):  
T. Globus ◽  
H. C. Slade ◽  
M. Shur ◽  
M. Hack
Keyword(s):  
Thin Film ◽  
Activation Energy ◽  
Amorphous Silicon ◽  
Conduction Band ◽  
Energy Gap ◽  
Localized States ◽  
Flat Band ◽  
Gate Bias ◽  
Density Of Localized States ◽  
Wide Range

ABSTRACTWe have measured the current-voltage characteristics of amorphous silicon thin film transistors (a-Si TFTs) over a wide range of temperatures (20 to 160°C) and determined the activation energy of the channel current as a function of gate bias with emphasis on the leakage current and subthreshold regimes. We propose a new method for estimating the density of localized states (DOS) from the dependence of the derivative of activation energy with respect to gate bias. This differential technique does not require knowledge of the flat-band voltage (VFB) and does not incorporate integration over gate bias. Using this Method, we have characterized the density of localized states with energies in the range 0.15–1.2 eV from the bottom of the conduction band and have found a wide peak in the DOS in the range of 0.8–0.95 eV below the conduction band. We have also observed that the DOS peak in the lower half of the bandgap increases in magnitude and shifts towards the conduction band as a result of thermal and bias stress. We also measured an overall increase in the DOS in the upper half of the energy gap and an additional peak, centered at 0.2 eV below the conduction band, which appear due to the applied stress. These results are in qualitative agreement with the defect pool Model [1,2].

Oscillatory non-resonant interband Faraday rotation in InSb and PbTe—a new magneto-optical effect

1971 ◽  
Vol 321 (1546) ◽  
pp. 303-320 ◽  
Keyword(s):  
Magnetic Field ◽  
Conduction Band ◽  
Field Dependence ◽  
Faraday Rotation ◽  
Magnetic Field Dependence ◽  
Energy Gap ◽  
Landau Levels ◽  
Wide Range ◽  
Magneto Optical Effect ◽  
The Magnetic Field

Oscillations in the magnetic field dependence of interband Faraday rotation in degenerate samples of InSb and PbTe at low temperatures have been observed for photons having a wide range of energies which are less than that corresponding to the forbidden energy gap. These oscillations are attributed to the imbalance of contributions from right and left circularly polarized modes to the total rotation, caused by the blocking of certain interband absorptions by conduction-band electrons. The perturbing effect of the variation of carrier concentration is used as an experimental variable. The relative strengths of the oscillations have been reasonably well accounted for by analysis of the interband selection rules and transition strengths given by a theory due to Boswarva & Lidiard. The positions of the oscillations, which depend on the population of Landau levels in the conduction band, have a reciprocal magnetic field dependence as for the de Haas-van Alphen effect, and have yielded quantitative determinations of energy-band parameters.

Electron transport and conduction band structure of GaSb

1981 ◽  
Vol 59 (12) ◽  
pp. 1844-1850 ◽  
Author(s):  
Hyung Jae Lee ◽  
John C. Woolley
Keyword(s):  
Magnetic Field ◽  
Experimental Data ◽  
Electrical Conductivity ◽  
Conduction Band ◽  
Room Temperature ◽  
Energy Gap ◽  
Band Model ◽  
Scattering Coefficients ◽  
Wide Range ◽  
Different Temperatures

Calculations have been made using the Fletcher and Butcher method in a three conduction band model to fit a wide range of experimental transport data for n-type samples of GaSb: viz. Hall coefficient and electrical conductivity as a function of temperature and as a function of pressure at room temperature, magnetoresistance as a function of magnetic field at different temperatures, and Nernst–Ettingshausen coefficients as a function of magnetic field. Various energy gap parameters and scattering coefficients have been taken as adjustable and values determined for these which give good fits to all of the experimental data. Values of mobility for each of the Γ, L, and X bands have then been calculated as a function of temperature.

The optical properties and chemical decomposition of lead iodide

1964 ◽  
Vol 280 (1383) ◽  
pp. 566-585 ◽  
Keyword(s):  
Optical Properties ◽  
Absorption Spectrum ◽  
Valence Band ◽  
Conduction Band ◽  
Electron Irradiation ◽  
Irradiation Damage ◽  
Lead Iodide ◽  
Chemical Decomposition ◽  
Excitation Processes ◽  
Split Valence

The optical properties of lead iodide have been measured and the fundamental absorption spectrum is interpreted in terms of ionization and excitation processes. These processes may be regarded as transitions from a split valence band to the conduction band and to exciton levels lying above and below the minimum of the conduction band. This inter­pretation is supported by measurements of photoconductivity and photodecomposition. Two mechanisms are suggested to explain the occurrence of photodecomposition and electron irradiation damage in this substance.

scholarly journals Effects of Zinc Binding on the Structure and Stability of Glycylglycine Dipeptide: A Computational Study

2012 ◽  
Vol 9 (3) ◽  
pp. 1244-1250 ◽  
Author(s):  
Mohammad T. Baei ◽  
S. Zahra Sayyad-Alangi
Keyword(s):  
Electronic Properties ◽  
Energy Gap ◽  
Computational Study ◽  
Bidentate Ligand ◽  
Zinc Binding ◽  
Basis Sets ◽  
Stable Complex ◽  
Stable Isomer ◽  
Zinc Cation ◽  
Homo Lumo

Energies and structures of six different isomers resulted of complex between glycylglycine dipeptide and zinc cation were calculated at the BLYP and B3LYP levels of theory with 6-311G** and 6-311++G** basis sets. The energies of the glycylglycine-Zn2+different complexes at the BLYP/6-311++G** obtained more stable than another methods. In this method, the most stable complex was zinc cation bound to the two oxygen sites of the glycylglycine zwitterion and acted as a bidentate ligand. The vibrational frequencies, thermodynamic and electronic properties, HOMO, LUMO, and energy gap for the most stable isomer in different solvents were calculated at the BLYP/6-311++G** level of theory.

scholarly journals Optical Properties of Ferrite Powders of NixCo1-xFe2O4 System

2015 ◽  
Vol 16 (3) ◽  
pp. 506-510
Author(s):  
V.S. Bushkova
Keyword(s):  
Optical Properties ◽  
Band Gap ◽  
Valence Band ◽  
Absorption Spectra ◽  
Conduction Band ◽  
Optical Band Gap ◽  
Sol Gel ◽  
Direct Transition ◽  
Nickel Cobalt ◽  
Auto Combustion

The aim of this work was to create and study of ferrite nickel-cobalt powders, using sol-gel technology with participation of auto-combustion. It is studied the optical properties of the powders depending on the degree of substitution of cobalt cations on nickel cations. As a result of analysis of the absorption spectra is revealed that for all investigated powders inherent allowed direct transition of electrons from the valence band to the conduction band.  It was shown that the optical band gap increases with increasing concentration of nickel cations in the composition of ferrites.

Electronic properties of particle-counting diamonds - Electronic properties of particle-counting diamonds I. Photoconductivity

1967 ◽  
Vol 262 (1126) ◽  
pp. 251-276 ◽  
Keyword(s):  
Thermal Decomposition ◽  
Experimental Investigation ◽  
Optical Properties ◽  
Electronic Properties ◽  
Valence Band ◽  
Room Temperature ◽  
Energy Gap ◽  
Intrinsic Absorption ◽  
Particle Counting ◽  
Temperature Spectra

An account is given of an experimental investigation into the photoconductivity of particle-counting diamonds at room temperature and at 80 °K. Photoconduction spectra were obtained in the range 2500 to 200 nm which are typical of type la diamonds. The room temperature spectra are characterized by a system of eight photoconduction peaks. The peaks are attributed to the intrinsic absorption, the thermal decomposition of excitons and the excitation of three levels in the forbidden energy gap at 0-85, 1.45 and 2.2 eV from the valence band. This model is consistent with the known electro-optical properties of type la diamonds. The model is formulated mathematically and formally shown to predict the observed photoconduction responses of the diamonds to certain characteristic illuminations.

scholarly journals Tuning Electronic Properties of the SiC-GeC Bilayer by External Electric Field: A First-Principles Study

Micromachines ◽  
2019 ◽  
Vol 10 (5) ◽  
pp. 309
Author(s):  
Min Luo ◽  
Bin Yu ◽  
Yu-e Xu
Keyword(s):  
Band Structure ◽  
Electric Field ◽  
Fermi Level ◽  
Electronic Properties ◽  
External Electric Field ◽  
Valence Band ◽  
Conduction Band ◽  
First Principles ◽  
First Principles Calculations ◽  
Direct Bandgap

First-principles calculations were used to investigate the electronic properties of the SiC/GeC nanosheet (the thickness was about 8 Å). With no electric field (E-field), the SiC/GeC nanosheet was shown to have a direct bandgap of 1.90 eV. In the band structure, the valence band of the SiC/GeC nanosheet was mainly made up of C-p, while the conduction band was mainly made up of C-p, Si-p, and Ge-p, respectively. Application of the E-field to the SiC/GeC nanosheet was found to facilitate modulation of the bandgap, regularly reducing it to zero, which was linked to the direction and strength of the E-field. The major bandgap modulation was attributed to the migration of C-p, Si-p, and Ge-p orbitals around the Fermi level. Our conclusions might give some theoretical guidance for the development and application of the SiC/GeC nanosheet.

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