Photoluminescence spectra of Zn1−xCdxAl2Se4-4xS4x single crystals

2000 ◽  
Vol 15 (12) ◽  
pp. 2690-2694 ◽  
Author(s):  
Sung-Hyu Choe ◽  
Chang-Sun Yoon ◽  
Moon-Seog Jin ◽  
Seung-Cheol Hyun ◽  
Chang Dae Kim ◽  
...  
Keyword(s):  
Single Crystals ◽  
Emission Band ◽  
Energy Gap ◽  
Visible Region ◽  
Chalcopyrite Structure ◽  
Broad Emission Band ◽  
Photoluminescence Spectra ◽  
Chemical Transport Reaction ◽  
Transport Reaction ◽  
Optical Energy

We investigated the photoluminescence as well as the crystal structure and optical energy gaps of the Zn1-xCdxAl2Se4-4xS4x solid solution system based on the Al-related compounds of ZnAl2Se4, ZnAl2S4, CdAl2Se4, and CdAl2S4. The single crystals of the system with 0.0 ≤ x ≤ 1.0 were grown by the chemical transport reaction technique. The Zn1-xCdxAl2Se4-4xS4x crystallizes in a defect chalcopyrite structure for a whole composition and has an optical energy gap ranging from 3.525 to 3.577 eV at 13 K. The photoluminescence spectra at 13 K showed a strong emission band in the blue spectral region and a weak broad emission band in the visible region due to donor–acceptor pair recombination. The composition and temperature dependence of these bands were examined in the investigated regions. The simple energy band scheme for the radiative mechanisms of the Zn1-xCdxAl2Se4-4xS4x is proposed on the basis of our experimental results along with photo-induced current transient spectroscopy measurements.

Optical properties of Ho3+-, Er3+-, and Tm3+-doped BaIn2S4 and BaIn2Se4 single crystals

2002 ◽  
Vol 17 (8) ◽  
pp. 2147-2152 ◽  
Author(s):  
Sang-An Park ◽  
Mi-Yang Kim ◽  
Wha-Tek Kim ◽  
Moon-Seog Jin ◽  
Sung-Hyu Choe ◽  
...  
Keyword(s):  
Single Crystals ◽  
Energy Gap ◽  
Photoluminescence Spectra ◽  
Optical Energy Gap ◽  
Acceptor Pair ◽  
Chemical Transport Reaction ◽  
Transport Reaction ◽  
Optical Energy ◽  
Broad Emission ◽  
Donor Acceptor

BaIn2S4, BaIn2S4:Ho3+, BaIn2S4:Er3+, BaIn2S4:Tm3+, BaIn2Se4, BaIn2Se4:Ho3+, BaIn2Se4:Er3+, and BaIn2Se4:Tm3+ single crystals were grown by the chemical transport reaction method. The optical energy gap of the single crystals was found to be 3.057, 2.987, 2.967, 2.907, 2.625, 2.545, 2.515, and 2.415 eV, respectively, at 11 K. The temperature dependence of the optical energy gap was well fitted by the Varshni equation. Broad emission peaks were observed in the photoluminescence spectra of the single crystals. They were assigned to donor–acceptor pair recombination. Sharp emission peaks were observed in the doped single crystals. They were attributed to be due to radiation recombination between the Stark levels of the Ho3+, Er3+, and Tm3+ ions sited in C1 symmetry.

Photoluminescence Spectra of Zn1-xCdxAl2Se4 Single Crystals

2000 ◽  
Vol 15 (4) ◽  
pp. 880-883 ◽  
Author(s):  
Seung-Cheol Hyun ◽  
Chang-Dae Kim ◽  
Tae-Young Park ◽  
Hyung-Gon Kim ◽  
Moon-Seog Jin ◽  
...  
Keyword(s):  
Single Crystals ◽  
Lattice Constant ◽  
Energy Band ◽  
Emission Band ◽  
Chalcopyrite Structure ◽  
Photoluminescence Spectra ◽  
Blue Emission Band ◽  
Optical Energy ◽  
Energy Gaps ◽  
Optical Energy Gaps

We investigated the photoluminescence spectra as well as the crystal structure and optical energy gaps of the Zn1-xCdxAl2Se4 single crystals grown by the chemical transport reaction method. It was shown from the analysis of the observed x-ray diffraction patterns that these crystals have a defect chalcopyrite structure for a whole composition. The lattice constant a increases from 5.5561 A for x = 0.0 (ZnAl2Se4) to 5.6361 A for x = 1.0 (CdAl2Se4) with increasing x, whereas the lattice constant c decreases from 10.8890 A for x = 0.0 to 10.7194 A for x = 1.0. The optical energy gaps at 13 K were found to range from 3.082 eV (x = 1.0) to 3.525 eV (x = 0.0). The temperature dependence of the optical energy gaps was well fitted with the Varshni equation. We observed two emission bands consisting of a strong blue emission band and a weak broad emission band due to donor–acceptor pair recombination in the Zn1-xCdxAl2Se4 for 0.0 ⩽ x ⩽ 1.0. These emission bands showed a red shift with increasing x. The energy band scheme for the radiative mechanism of the Zn1-xCdxAl2Se4 was proposed on the basis of the photoluminescence thermal quenching analysis along with the measurements of photo-induced current transient spectroscopy. The proposed energy band model permits us to assign the observed emission bands.

Photoluminescence spectra of undoped and Sm3+-doped BaAl2S4 and BaAl2Se4 single crystals

2001 ◽  
Vol 16 (5) ◽  
pp. 1520-1524 ◽  
Author(s):  
Moon-Seog Jin ◽  
Choong-Il Lee ◽  
Chang-Sun Yoon ◽  
Chang-Dae Kim ◽  
Jae-Mo Goh ◽  
...  
Keyword(s):  
Single Crystals ◽  
Energy Levels ◽  
Photoluminescence Spectra ◽  
Acceptor Pair ◽  
Chemical Transport Reaction ◽  
Ionic Radii ◽  
Transport Reaction ◽  
Broad Emission ◽  
Electron Transitions ◽  
Donor Acceptor

Undoped and Sm3+-doped BaAl2S4 and BaAl2Se4 single crystals were grown by the chemical transport reaction method. The optical energy band gaps of the BaAl2S4 and BaAl2Se4 were found to be 4.10 and 3.47 eV, respectively, at 5 K. In their photoluminescence spectra measured at 5 K, broad emission peaks at 459 and 601 nm appeared in the BaAl2S4 and at 486 and 652 nm in the BaAl2Se4. These emissions are assigned to donor–acceptor pair recombinations. Sharp emission peaks were observed in the Sm3+-doped BaAl2S4 and BaAl2Se4 single crystals at 5 K. Taking into account the ionic radii of the cations and Sm3+, these sharp emission peaks are attributed to the electron transitions between the energy levels of Sm3+ substituting with the Ba site.

On the preparation of Fe7Se8 single crystals by a chemical transport reaction

1974 ◽  
Vol 9 (9) ◽  
pp. 1267-1272 ◽  
Author(s):  
A. Paja̧czkowska ◽  
P. Peshev ◽  
M. Ivanova ◽  
R. Gałazka
Keyword(s):  
Single Crystals ◽  
Chemical Transport ◽  
Chemical Transport Reaction ◽  
Transport Reaction

scholarly journals Optical Properties of CaNb2O6 Single Crystals Grown by OFZ*

Crystals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 928
Author(s):  
Guanlin Feng ◽  
Liang Li ◽  
Dapeng Xu
Keyword(s):  
Refractive Index ◽  
Optical Properties ◽  
Absorption Coefficient ◽  
Single Crystals ◽  
Infrared Region ◽  
Broad Emission Band ◽  
Floating Zone ◽  
Photoluminescence Spectra ◽  
Direct Transition ◽  
Broad Emission

CaNb2O6 single crystals with an orthorhombic columbite structure are grown via an optical floating zone (OFZ) method. The as-grown crystals are colorless and free of low-angle grain boundaries and inclusions. They are transparent (up to 62%) in the visible to the infrared region (400–1000 nm) and have a low absorption coefficient (α = 1.56). The bandgap is determined as a direct transition and Eg = 4.28 eV. The wavelength-dependent refractive index and extinction coefficient of the CaNb2O6 crystals are derived from the obtained T and α spectra. Their photoluminescence spectra exhibit a strong and broad emission band centered at 465 nm.

Absorption spectra of Co2+ in AgInS2 orthorhombic single crystals

2001 ◽  
Vol 16 (4) ◽  
pp. 975-978 ◽  
Author(s):  
Hidong Kim ◽  
Seok-Joo Lee ◽  
Jae-Eun Kim ◽  
Hae Yong Park ◽  
Seok-Kyun Oh ◽  
...  
Keyword(s):  
Single Crystals ◽  
Absorption Spectra ◽  
Chemical Transport ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Chemical Transport Reaction ◽  
Transport Reaction ◽  
Electronegativity Difference ◽  
Crystal Field Parameters ◽  
The Ideal

The optical absorption spectra of AgInS2:Co2+ single crystals grown by chemical transport reaction using iodine as a transporting medium have been studied at 6 K. The peaks can be explained by the transitions of Co2+ in the Td symmetry with the spin-orbit coupling, which means that the deviations of the atomic sites from those of the ideal wurtzite structure can be considered negligibly small. The consideration of both the crystal field parameters and the electronegativity difference between atoms may indicate that Co atoms substitute In atoms.

Thermopower, Electrical and Hall Conductivity of Undoped and Doped Iron Disilicide Single Crystals

1997 ◽  
Vol 478 ◽  
Author(s):  
A. Heinrich ◽  
G. Behr ◽  
H. Griessmann ◽  
S. Teichert ◽  
H. Lange
Keyword(s):  
Transport Properties ◽  
Single Crystals ◽  
Electrical Transport ◽  
Impurity Band ◽  
Hall Conductivity ◽  
Electrical Transport Properties ◽  
Chemical Transport Reaction ◽  
Intrinsic Defects ◽  
Transport Reaction ◽  
Mobility Data

AbstractThe electrical transport properties of β-FeSi2 single crystals have been investigated in dependence on the purity of the source material and on doping with 3d transition metals. The transport properties included are electrical conducticvity, Hall conductivity and thermopower mainly in the temperature range from 4K to 300K. The single crystals have been prepared by chemical transport reaction in a closed system with iodine as transport agent. In undoped single crystals prepared with 5N Fe both electrical conductivity and thermopower depend on the composition within the homogeinity range of β-FeSi2 which is explained by different intrinsic defects at the Sirich and Fe-rich phase boundaries. In both undoped and doped single crystals impurity band conduction is observed at low temperatures but above 100K extrinsic behaviour determined by shallow impurity states. The thermopower shows between 100K and 200K a significant phonon drag contribution which depends on intrinsic defects and additional doping. The Hall resistivity is considered mainly with respect to an anomalous contribution found in p-type and n-type single crystals and thin films. In addition doped single crystals show at temperatures below about 130K an hysteresis of the Hall voltage. These results make former mobility data uncertain. Comparison will be made between the transport properties of single crystals and polycrystalline material.

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