scholarly journals Optical band gap and infrared phonon modes of (La_029Sr_071)(Al_065Ta_036)O_3 (LSAT) single crystal from infrared to ultraviolet range spectroscopic ellipsometry

2016 ◽  
Vol 6 (10) ◽  
pp. 3210 ◽  
Author(s):  
A. Barnes ◽  
H. Haneef ◽  
D. G. Schlom ◽  
N. J. Podraza
Keyword(s):  
Single Crystal ◽  
Band Gap ◽  
Spectroscopic Ellipsometry ◽  
Optical Band Gap ◽  
Phonon Modes ◽  
Ultraviolet Range

scholarly journals Resonance and antiresonance in Raman scattering in GaSe and InSe crystals

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
M. Osiekowicz ◽  
D. Staszczuk ◽  
K. Olkowska-Pucko ◽  
Ł. Kipczak ◽  
M. Grzeszczyk ◽  
...  
Keyword(s):  
Raman Scattering ◽  
Temperature Effect ◽  
Band Gap ◽  
Raman Spectra ◽  
Quantum Interference ◽  
Optical Band Gap ◽  
Phonon Coupling ◽  
Phonon Modes ◽  
Electron Phonon Coupling ◽  
Resonant Raman

AbstractThe temperature effect on the Raman scattering efficiency is investigated in $$\varepsilon$$ ε -GaSe and $$\gamma$$ γ -InSe crystals. We found that varying the temperature over a broad range from 5 to 350 K permits to achieve both the resonant conditions and the antiresonance behaviour in Raman scattering of the studied materials. The resonant conditions of Raman scattering are observed at about 270 K under the 1.96 eV excitation for GaSe due to the energy proximity of the optical band gap. In the case of InSe, the resonant Raman spectra are apparent at about 50 and 270 K under correspondingly the 2.41 eV and 2.54 eV excitations as a result of the energy proximity of the so-called B transition. Interestingly, the observed resonances for both materials are followed by an antiresonance behaviour noticeable at higher temperatures than the detected resonances. The significant variations of phonon-modes intensities can be explained in terms of electron-phonon coupling and quantum interference of contributions from different points of the Brillouin zone.

scholarly journals CH3NH3PbI3 perovskite single crystals: surface photophysics and their interaction with the environment

2015 ◽  
Vol 6 (12) ◽  
pp. 7305-7310 ◽  
Author(s):  
G. Grancini ◽  
V. D'Innocenzo ◽  
E. R. Dohner ◽  
N. Martino ◽  
A. R. Srimath Kandada ◽  
...  
Keyword(s):  
Single Crystal ◽  
Band Gap ◽  
Single Crystals ◽  
Optical Band Gap ◽  
Structural Inhomogeneity ◽  
Highly Sensitive ◽  
Micrometer Scale ◽  
Local Modulation

Structural inhomogeneity on a micrometer-scale across a CH3NH3PbI3 single crystal is responsible for a local modulation of the optical band gap, which is also highly sensitive to humidity.

Temperature Dependence of Phonon Modes, Optical Constants, and Optical Band Gap in Two-Dimensional ReS2 Films

2018 ◽  
Vol 122 (51) ◽  
pp. 29464-29469
Author(s):  
Keyang Zhao ◽  
Fanming Huang ◽  
Chen-Min Dai ◽  
Wenwu Li ◽  
Shi-You Chen ◽  
...  
Keyword(s):  
Temperature Dependence ◽  
Band Gap ◽  
Optical Constants ◽  
Optical Band Gap ◽  
Two Dimensional ◽  
Phonon Modes

Optical and Electronic Analysis of Pure and Fe-Doped ZnO Thin Films Using Spectroscopic Ellipsometry and Kramers–Kronig Method

2019 ◽  
Vol 18 (01) ◽  
pp. 1850013 ◽  
Author(s):  
Maryam Motallebi Aghgonbad ◽  
Hassan Sedghi
Keyword(s):  
Thin Films ◽  
Band Gap ◽  
Spectroscopic Ellipsometry ◽  
Optical Band Gap ◽  
Band Gap Energy ◽  
Zno Thin Films ◽  
Fe Doping ◽  
Gap Energy ◽  
Optical And Electronic Properties ◽  
Doped Zno

In the present work, pure and Fe-doped ZnO thin films were deposited on glass substrates by sol–gel method. Zinc acetate and iron nitrate were used as the starting material and dopant source, respectively. The concentration of Fe doping was 6[Formula: see text]at.% and 8[Formula: see text]at.%. The optical and electronic properties of pure and Fe-doped ZnO thin films such as refraction index, extinction coefficient, dielectric function and optical band gap energy of the layers were obtained by spectroscopic ellipsometry method in the wavelength range of 300–900[Formula: see text]nm. The incidence angle of the layers kept 70[Formula: see text]. Also data obtained by Kramers–Kronig relations were used for comparison. The influence of Fe-doping concentration on the optical and electronic properties of thin films was studied. The transmittance data of ZnO thin films showed that 6[Formula: see text]at.% Fe-doped ZnO thin film has the highest transmittance value. Dielectric function of pure ZnO films was found to be higher compared with Fe-doped ones. Also it can be deduced from the results that Fe doping influences the optical band gap energy of thin films.

Investigation of optical band gap in potassium acid phthalate single crystal

2008 ◽  
Vol 43 (6) ◽  
pp. 670-673 ◽  
Author(s):  
S. Krishnan ◽  
C. Justin Raj ◽  
S. Dinakaran ◽  
S. Jerome Das
Keyword(s):  
Single Crystal ◽  
Band Gap ◽  
Optical Band Gap ◽  
Potassium Acid Phthalate ◽  
Acid Phthalate

scholarly journals Analyzing of Optical Band Gap in Bis Glycine Cobalt Sulfate Single Crystal

2012 ◽  
Vol 7 (3) ◽  
pp. 290-294
Author(s):  
G. Shankar ◽  
G. Anbazhagan ◽  
P.S. Joseph ◽  
T. Balakrishn
Keyword(s):  
Single Crystal ◽  
Band Gap ◽  
Optical Band Gap ◽  
Cobalt Sulfate

Influence of Al content on the optical band-gap enhancement and lattice structure of (Ga1-xAlx)2O3 single crystal

2020 ◽  
Vol 109 ◽  
pp. 110351 ◽  
Author(s):  
Indranil Bhaumik ◽  
M. Soharab ◽  
R. Bhatt ◽  
A. Saxena ◽  
S. Sah ◽  
...  
Keyword(s):  
Single Crystal ◽  
Band Gap ◽  
Optical Band Gap ◽  
Lattice Structure ◽  
Al Content

scholarly journals Effect of L-asparagine as dopant on the growth and characteristics of ammonium tetroxalate dihydrate single crystal

2020 ◽  
Vol 38 (1) ◽  
pp. 48-61
Author(s):  
Eunice Jerusha ◽  
S. Shahil Kirupavathy
Keyword(s):  
Single Crystal ◽  
Band Gap ◽  
Optical Band Gap ◽  
Vickers Microhardness ◽  
Thermal Studies ◽  
Visible Region ◽  
Hysteresis Loops ◽  
Dielectric Behavior ◽  
X Ray Diffraction ◽  
Polarization Electric Field

AbstractSingle crystals of L-asparagine doped ammonium tetroxalate dihydrate were grown using slow evaporation solution growth technique with deionized water as a solvent. The shift and intensity of the peaks in the single crystal X-ray diffraction and Fourier transform infrared analyses confirmed the inclusion of L-asparagine in the ammonium tetroxalate dihydrate crystal structure. The optical transmission characteristics viz. optical band gap, optical conductivity, etc., were determined. Thermal studies revealed the occurrence of anomalies at 135.3 °C and 221.7 °C leading to the possibility of phase transitions and thereby, ferroelectric behavior. Vickers microhardness studies enabled determination of various microhardness parameters. Dielectric behavior was analyzed by varying the temperature and frequency. Anomalies were observed at 135 °C and 221 °C suggesting the existence of ferroelectric nature of the compound. Self-defocusing effect was observed. The polarization-electric field hysteresis loops showed a pinched effect due to defects induced by inclusion of dopant. The crystals were characterized by single crystal XRD, FT-IR, DRS, UV-Vis-NIR, Vickers microhardness test as well as thermal and dielectric techniques. In brief, L-asparagine as a dopant in ammonium tetroxalate dihydrate altered various physical properties of the crystals. They were highly transparent in the visible region with a wider optical band gap, softer material than the parent, higher phase transition temperature of 135 °C, negative nonlinearity and self-defocusing ability.

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