Temperature dependence of the optical band gap of nearly perfect K2ZnCl4 single crystals in the ferroelectric phase

1999 ◽  
Vol 271 (1-4) ◽  
pp. 205-211 ◽  
Author(s):  
A. El-Korashy ◽  
A. Abu El-Fadl
1993 ◽  
Vol 150 (1) ◽  
pp. 343-350 ◽  
Author(s):  
M. Osman ◽  
A. El-Korashy ◽  
H. El-Zahed

Author(s):  
И.В. Боднарь ◽  
Б.Т. Чан ◽  
В.Н. Павловский ◽  
И.Е. Свитенков ◽  
Г.П. Яблонский

AbstractMnAgIn_7S_12 single crystals 16 mm in diameter and ~40 mm in length are grown by planar crystallization of the melt. It is shown that the material grown crystallizes with the formation of the cubic spinel structure. From the transmittance spectra recorded in the region of fundamental absorption in the temperature range 10–320 K, the band gap E _ g of the single crystals and its temperature dependence are determined. The dependence has a shape typical of most semiconductor materials: as the temperature is lowered, the band gap E _ g increases. A calculation is carried out, and it is shown that the calculated values are in agreement with the experimental data.


2020 ◽  
Vol 11 (7) ◽  
pp. 2490-2496 ◽  
Author(s):  
Giovanni Mannino ◽  
Ioannis Deretzis ◽  
Emanuele Smecca ◽  
Antonino La Magna ◽  
Alessandra Alberti ◽  
...  

2015 ◽  
Vol 6 (12) ◽  
pp. 7305-7310 ◽  
Author(s):  
G. Grancini ◽  
V. D'Innocenzo ◽  
E. R. Dohner ◽  
N. Martino ◽  
A. R. Srimath Kandada ◽  
...  

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.


2013 ◽  
Vol 200 ◽  
pp. 50-53
Author(s):  
Inna A. Ivashchenko ◽  
Volodumur V. Halyan ◽  
Irina V. Danylyuk ◽  
Volodumur Z. Pankevuch ◽  
Georgij Y. Davydyuk ◽  
...  

The phase diagram of the Ga2Se3–In2Se3 system was investigated by differential-thermal analysis (DTA) and X-ray diffraction (XRD) method. The single crystals from the area of existence of the γ2 phase with the compositions (Ga0.6In0.4)2Se3 and (Ga0.594In0.396Er0.01)2Se3 were grown by a vertical Bridgman method. Absorption spectra of the grown crystals were studied. The estimated optical band gap is 1.95±0. 01 eV. The resistance of the single crystals of (Ga0.6In0.4)2Se3 (R=500 MΩ) and (Ga0.594In0.396Er0.01)2Se3 (R=210 MΩ) was measured.


2020 ◽  
Vol 53 (4) ◽  
pp. 972-981 ◽  
Author(s):  
G. Durgababu ◽  
G. J. Nagaraju ◽  
G. Bhagavannarayana

Good quality single crystals of 2,4-dinitrophenol (DNP)-doped tristhioureazinc(II) sulfate (ZTS) were successfully grown by employing the simple and cost effective slow-evaporation solution technique. To study the effect of doping on various device properties, the grown single crystals were subjected to powder X-ray diffraction (PXRD), high-resolution XRD, thermogravimetric analysis (TGA), Vickers hardness testing, and UV–visible, photoluminescence (PL) and Fourier transform IR (FTIR) spectroscopy techniques. The crystal structure of DNP-doped ZTS bulk single crystals remained the same as the crystal structure of ZTS. However, the changes in intensities of the diffraction peaks in the PXRD spectra indicated the incorporation of dopants into the crystalline matrix. FTIR studies confirm the incorporation of dopants into the crystalline matrix, shown by the shifting of certain prominent absorption bands towards higher energy. This also indicated the induced useful strain due to doping, leading to charge transfer and the enhancement of nonlinear optical properties. The cut-off wavelength and optical band gap energy of pure ZTS and DNP-doped ZTS crystals were studied by UV–visible absorption spectroscopy, revealing a slight reduction in the optical band gap energy due to doping, which in turn revealed the enhancement of the optical range. PL studies revealed an enhanced optical range of photoluminescence in ZTS crystals. Second harmonic generation (SGH) studies carried out by the Kurtz powder technique revealed the enhancement of SHG value due to DNP doping. To ensure the thermal stability and mechanical strength of the grown crystals with doping (required from the point of view of device applications), TGA and Vicker's hardness studies were performed.


2019 ◽  
Vol 53 (12) ◽  
pp. 1593-1596
Author(s):  
I. V. Bodnar ◽  
B. T. Chan ◽  
V. N. Pavlovskii ◽  
I. E. Svitsiankou ◽  
G. P. Yablonskii

2020 ◽  
Vol 87 (5) ◽  
pp. 820-824
Author(s):  
I. I. Bodnar ◽  
V. N. Pavlovskii ◽  
I. E. Svitsiankou ◽  
G. P. Yablonskii

2006 ◽  
Vol 3 (8) ◽  
pp. 2665-2668 ◽  
Author(s):  
Duck-Tae Kim ◽  
Sang-An Park ◽  
Woon-Jo Jeong ◽  
Gye-Choon Park ◽  
Moon-Seog Jin ◽  
...  

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