Insights into the structural, electronic and optical properties of MgA2B4(A = Sc, Y; B = S, Se) spinel compounds: Direct energy band gap materials

2021 ◽  
Vol 127 ◽  
pp. 105736
Author(s):  
Muhammad Saeed ◽  
Zubaida Noor ◽  
Amel Laref ◽  
Hind Althib ◽  
Tahani H. Flemban ◽  
...  
Keyword(s):  
Optical Properties ◽  
Band Gap ◽  
Energy Band ◽  
Energy Band Gap ◽  
Electronic And Optical Properties ◽  
Spinel Compounds ◽  
Direct Energy

STRUCTURAL, ELASTIC, ELECTRONIC, CHEMICAL BONDING AND OPTICAL PROPERTIES OF M2Se (M = Li, Na, K, Rb) THROUGH FIRST PRINCIPLE STUDY

2013 ◽  
Vol 27 (30) ◽  
pp. 1350170 ◽  
Author(s):  
ROSHAN ALI ◽  
R. KHANATA ◽  
BIN AMIN ◽  
G. MURTAZA ◽  
S. BIN OMRAN
Keyword(s):  
Optical Properties ◽  
Band Gap ◽  
Chemical Bonding ◽  
Energy Band ◽  
Electronic Band Structure ◽  
Full Potential ◽  
Energy Band Gap ◽  
Electronic Band ◽  
Direct Energy ◽  
Metal Selenides

Structural, elastic, electronic and optical properties as well as chemical bonding of the binary alkali metal selenides M 2 Se ( M = Li , Na , K , Rb ) were calculated using the full potential linearized augmented plane method. From the elastic constants it is inferred that these compounds are brittle in nature. The results of the electronic band structure show that Na 2 Se has a direct energy band gap (Γ-Γ), Li 2 Se has an indirect energy band gap (Γ- X), while K 2 Se and Rb 2 Se have an indirect energy band gap (X-Γ). Analysis of the charge distribution plots reveals a dominated ionic bonding in the herein studied compounds. Additionally, we have calculated the optical properties, namely, the real and the imaginary parts of the dielectric function, refractive index, extinction coefficient, optical conductivity and reflectivity for radiation up to 30.0 eV. All these compounds have direct energy band gap greater than 3.1 eV suggesting their use for manufacturing high frequency devices.

scholarly journals Effect of Dopant Concentration on the Structural, Optical and Sensing Properties of (SnO2)1-x(TiO2:CuO)x Sprayed Films

2019 ◽  
Vol 16 (2) ◽  
pp. 0361
Author(s):  
Mahmood Et al.
Keyword(s):  
Optical Properties ◽  
Band Gap ◽  
Energy Band ◽  
Spray Pyrolysis Technique ◽  
Single Crystal Silicon ◽  
Dielectric Constants ◽  
Energy Band Gap ◽  
Crystal Silicon ◽  
X Ray ◽  
Regular Manner

      Spray pyrolysis technique was subjected to synthesized (SnO2)1-x (TiO2: CuO) x Thin films on different substrates like glass and single crystal silicon using. The structure of the deposited films was studied using x-ray diffraction. A more pronounced diffraction peaks of SnO2 while no peaks of (CuO , TiO2 ) phase appear in the X-ray profiles by increasing of the content of (TiO2 , CuO) in the sprayed films. Mixing concentration (TiO2 , CuO) influences on the size of the crystallites of the SnO2 films ,the size of crystallites of the spray paralyzed oxide films change in regular manner by increasing of (TiO2 , CuO) amount. The effect of mixing concentration on the optical properties of the films was also investigated. The reflectance and transmittance spectra  in the wavelength range (300-1100) nm were employed to determine the optical properties such as energy band gap (Eg) and refractive index (n),  extinction coefficient  (k) , real and imaginary parts of dielectric constants (ε1, ε2) for (SnO2)1-x(TiO2:CuO)x films. The energy band gap omit of which showed reduction from (3.65 to 2.2) eV by reducing of SnO2 amount from (100 to 70) % .The reduction of energy band gap was ascribed to the new tail states introduced in the band gap of tin oxide. The sensitivity of the prepared sensor film was determined resistance difference of the films when exposed to oxidizing gas. The data declared that the mixed SnO2 films have better sensitivity in comparison with unmixed films.

Characterization of Tb-doped hydroxyapatite for biomedical applications: optical properties and energy band gap determination

2017 ◽  
Vol 52 (17) ◽  
pp. 9990-10000 ◽  
Author(s):  
Y. Jiménez-Flores ◽  
M. Suárez-Quezada ◽  
J. B. Rojas-Trigos ◽  
L. Lartundo-Rojas ◽  
V. Suárez ◽  
...  
Keyword(s):  
Optical Properties ◽  
Band Gap ◽  
Energy Band ◽  
Biomedical Applications ◽  
Energy Band Gap

Structural and optical properties of PbI2 nanostructures obtained using the thermal evaporation method

2013 ◽  
Vol 91 (10) ◽  
pp. 826-832 ◽  
Author(s):  
Safaa I. Mohammed ◽  
Y. Al-Douri ◽  
U. Hashim ◽  
N.M. Ahmed ◽  
R. Al-Gaashani
Keyword(s):  
Grain Size ◽  
Optical Properties ◽  
Band Gap ◽  
Energy Band ◽  
Room Temperature ◽  
Crystal Size ◽  
Thermal Evaporation ◽  
Energy Band Gap ◽  
Thermal Evaporation Method ◽  
Evaporation Method

Lead iodide (PbI2) nanostructures were successfully prepared using the thermal evaporation method on a glass substrate at room temperature. The structural properties were analyzed using X-ray diffraction, which revealed that the crystal size increases as thickness increases. Crystal size was calculated to be in the range 27.3–61.08 nm. In addition, the preferred growth orientation was (001) for all samples. The surface morphologies using scanning electron microscopy have shown an increasing of grain size with increasing thickness. Also, optical properties using ultraviolet–visible spectroscopy were researched as a function of thickness. The absorption data have indicated direct transmission with optical energy band gap that varies continuously from 2.35 to 2.40 eV at room temperature. The refractive index and optical dielectric constant were investigated to verify the suitability of the model for electro-optical systems. The low fluctuation in energy band gap indicates that the grain size is quite small. The obtained results are in good agreement with experimental and theoretical data.

The observation of a direct energy band gap for CuInTe2 single crystals using electroreflectance techniques

1977 ◽  
Vol 23 (12) ◽  
pp. 905-906 ◽  
Author(s):  
M.J. Thwaites ◽  
R.D. Tomlinson ◽  
M.J. Hampshire
Keyword(s):  
Band Gap ◽  
Single Crystals ◽  
Energy Band ◽  
Energy Band Gap ◽  
Direct Energy

Electronic structure and optical properties of novel monolayer gallium nitride and boron phosphide heterobilayers

2018 ◽  
Vol 20 (44) ◽  
pp. 28124-28134 ◽  
Author(s):  
A. Mogulkoc ◽  
Y. Mogulkoc ◽  
M. Modarresi ◽  
B. Alkan
Keyword(s):  
Optical Properties ◽  
Electronic Structure ◽  
Gallium Nitride ◽  
Electric Field ◽  
Band Gap ◽  
External Electric Field ◽  
Charge Distribution ◽  
Energy Band ◽  
Energy Band Gap ◽  
Boron Phosphide

An external electric field modifies the electronic structure, charge distribution and energy band gap in the heterobilayer of gallium nitride/boron phosphide.

Optical Properties Of Tantalum Oxide Films Deposited On BK7 Substrates By Excimer Laser Ablation

2000 ◽  
Vol 617 ◽  
Author(s):  
S. Boughaba ◽  
M. U. Islam
Keyword(s):  
Optical Properties ◽  
Laser Ablation ◽  
Band Gap ◽  
Energy Band ◽  
Tantalum Oxide ◽  
Energy Band Gap ◽  
Optical Energy ◽  
Extinction Coefficients ◽  
Glass Substrates ◽  
Optical Energy Band Gap

AbstractThin amorphous films of tantalum oxide were grown on borosilicate crown glass substrates by KrF excimer pulsed laser ablation of a Ta2O5 target, in an oxygen environment. The deposition was performed at a temperature of 250 or 400 °C, while the oxygen pressure was set in the range 5 to 30 mTorr. The optical properties of the tantalum oxide coatings, as evaluated by reflectance/transmittance spectrophotometry, were found to be dependent on the oxygen gas pressure. At a pressure of 5 mTorr, absorbing films were obtained, with extinction coefficients above 10−2 (at λ=633 nm), along with an optical energy band-gap as low as 0.7 eV. At a pressure of 10 mTorr and above, the coatings had refractive indices up to 2.25 (at λ=633 nm), extinction coefficients below 10−4 (for λ>390 nm), and an optical energy band-gap in the range 3.9 to 4.0 eV.

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