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 ◽  
...  

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.

2002 ◽  
Vol 17 (8) ◽  
pp. 2147-2152 ◽  
Author(s):  
Sang-An Park ◽  
Mi-Yang Kim ◽  
Wha-Tek Kim ◽  
Moon-Seog Jin ◽  
Sung-Hyu Choe ◽  
...  

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.


2013 ◽  
Vol 827 ◽  
pp. 12-15
Author(s):  
Ya Fen Wu ◽  
Jiunn Chyi Lee

The optical properties of Cu-poor CuIn1-xGaxSe2 thin films with different gallium contents grown by co-evaporated technique were studied. Measurements of photoluminescence and photoreflectance were performed on the samples. The photoluminescence and photoreflectance emission peaks observed around 1.1 eV are attributed to donor-acceptor pair luminescence. These donor-acceptor pair emissions are considered to originate from relatively shallow acceptor and donor energy levels. With increasing gallium content, the emission peaks shift towards higher levels of photon energy, and the linewidths of the luminescence spectra for the samples become wider, which we attributes to the greater statistical disorder between indium and gallium. Moreover, the conversion efficiency of the CuIn1-xGaxSe2-based solar cells is obtained. The measured results coincide with the inference given by the photoluminescence spectra.


2000 ◽  
Vol 15 (12) ◽  
pp. 2690-2694 ◽  
Author(s):  
Sung-Hyu Choe ◽  
Chang-Sun Yoon ◽  
Moon-Seog Jin ◽  
Seung-Cheol Hyun ◽  
Chang Dae Kim ◽  
...  

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.


1987 ◽  
Vol 65 (3) ◽  
pp. 204-207 ◽  
Author(s):  
S. Charbonneau ◽  
E. Fortin ◽  
J. Beauvais

Photoluminescence spectra of CdIn2S4 single crystals at 1.8 K under both continuous-wave (CW) and pulsed excitation were obtained. In the latter case, a variable time-window technique was used to observe the time evolution of the spectra between 0 and 100 μs. In contrast to previous studies, four spectral bands were observed under both CW and pulsed, intrinsic or extrinsic excitation. In particular, two bands previously unobserved under extrinsic excitation were detected at 1.35 and 1.68 eV, and have been attributed to donor–acceptor pairs and free-electron to acceptor transitions respectively.


1974 ◽  
Vol 9 (9) ◽  
pp. 1267-1272 ◽  
Author(s):  
A. Paja̧czkowska ◽  
P. Peshev ◽  
M. Ivanova ◽  
R. Gałazka

1996 ◽  
Vol 442 ◽  
Author(s):  
Kenji Yoshino ◽  
Kouji Maeda ◽  
Atsuhiko Fukuyama ◽  
Yoshito Akashi ◽  
Kiyohisa Imada ◽  
...  

AbstractThe photoluminescence measurements of alkaline metal doped zincselenide (ZnSe) single crystals were carried out to investigate how the impurity atoms substitute the intrinsic vacancy. Sample are grown by the sublimation method and the Li and Na with the concentrations of 0.1, 0.25 and 0.5 mol% were incorporated simultaneously. In the PL spectra with lower impurity concentrations, bound exciton lines of deep acceptor and donor-acceptor pair (DAP) bands were clearly observed accompanied by a weak free exciton line. Although the bound exciton lines becomes smaller with increasing the impurity concentration, the DAP band remains strong and its peak energy shift to lower energy side with the concentration. The decrease of the bound exciton lines is drastic for Li-doped sample than Na-doped sample. This indicates that Li atoms more easily occupy the Zn vacancies than Na.


1999 ◽  
Vol 85 (6) ◽  
pp. 3198-3201 ◽  
Author(s):  
N. M. Gasanly ◽  
A. Serpengüzel ◽  
A. Aydinli ◽  
O. Gürlü ◽  
I. Yilmaz

Crystals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 928
Author(s):  
Guanlin Feng ◽  
Liang Li ◽  
Dapeng Xu

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.


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