The Experts below are selected from a list of 120 Experts worldwide ranked by ideXlab platform
Akira J Ikushima - One of the best experts on this subject based on the ideXlab platform.
-
effects of fluorine on structure structural relaxation and Absorption Edge in silica glass
Journal of Applied Physics, 2002Co-Authors: Kazuya Saito, Akira J IkushimaAbstract:The effects of fluorine (F) doping on silica glass structure, structural relaxations, and vacuum ultraviolet (VUV) Absorption Edge were investigated by the infrared and vacuum ultraviolet Absorption measurements. Linewidth of 2260 cm−1 Absorption band, which is one of the good indicators of structural disorder, decreases proportionally to the fictive temperature (Tf). On the other hand, it is irrespective of F concentration. Structural relaxations are strongly stimulated by F doping. The transparency near the Absorption Edge depends on both F concentration and Tf. When Tf is constant, Absorption Edge shifts to a shorter wavelength proportionally to the F concentration. These results strongly suggest that there are two main factors that control the VUV Absorption Edge of F-doped silica glass; band gap widening by increasing Si–F bond and reduction of structural disorder. The latter factor is not directly caused by structural change by F doping. F enhances the structural relaxation, and it is easy to obtain...
-
Absorption Edge in silica glass
Physical Review B, 2000Co-Authors: Kazuya Saito, Akira J IkushimaAbstract:Vacuum ultraviolet Absorption measurement was carried out in silica glass over a wide temperature range from 4 to 1900 K, and structure of the Absorption Edge and its origin have been elucidated. The main factor that determines the Urbach tail of silica glass is the thermal vibration rather than the structural disorder frozen-in at the glass transition temperature, resulting in a strong temperature dependence of the Absorption Edge far below the glass transition temperature. Furthermore, freezing process of the disorder from the viewpoint of electronic structure was observed.
Kazuya Saito - One of the best experts on this subject based on the ideXlab platform.
-
effects of fluorine on structure structural relaxation and Absorption Edge in silica glass
Journal of Applied Physics, 2002Co-Authors: Kazuya Saito, Akira J IkushimaAbstract:The effects of fluorine (F) doping on silica glass structure, structural relaxations, and vacuum ultraviolet (VUV) Absorption Edge were investigated by the infrared and vacuum ultraviolet Absorption measurements. Linewidth of 2260 cm−1 Absorption band, which is one of the good indicators of structural disorder, decreases proportionally to the fictive temperature (Tf). On the other hand, it is irrespective of F concentration. Structural relaxations are strongly stimulated by F doping. The transparency near the Absorption Edge depends on both F concentration and Tf. When Tf is constant, Absorption Edge shifts to a shorter wavelength proportionally to the F concentration. These results strongly suggest that there are two main factors that control the VUV Absorption Edge of F-doped silica glass; band gap widening by increasing Si–F bond and reduction of structural disorder. The latter factor is not directly caused by structural change by F doping. F enhances the structural relaxation, and it is easy to obtain...
-
Absorption Edge in silica glass
Physical Review B, 2000Co-Authors: Kazuya Saito, Akira J IkushimaAbstract:Vacuum ultraviolet Absorption measurement was carried out in silica glass over a wide temperature range from 4 to 1900 K, and structure of the Absorption Edge and its origin have been elucidated. The main factor that determines the Urbach tail of silica glass is the thermal vibration rather than the structural disorder frozen-in at the glass transition temperature, resulting in a strong temperature dependence of the Absorption Edge far below the glass transition temperature. Furthermore, freezing process of the disorder from the viewpoint of electronic structure was observed.
Pavel Hlídek - One of the best experts on this subject based on the ideXlab platform.
-
High temperature optical Absorption Edge of CdTe single crystal
Journal of Applied Physics, 2014Co-Authors: Eduard Belas, S. Uxa, Roman Grill, Pavel Hlídek, L. Šedivý, M. BugarAbstract:The optical Absorption Edge of bulk CdTe single crystal was measured by infrared transmission under saturated Cd pressure in the temperature interval 295–1223 K. The Absorption coefficient was directly determined up to the value of 100 cm−1. For higher values, it was estimated by extrapolating the spectra according to the Urbach exponential rule. It was observed that the common temperature-independent intersection of extrapolated Urbach Absorption Edge, the “Urbach focus,” does not exist in CdTe. The temperature dependence of band-gap energy Eg defined by Eg(300 K) = 1.518 eV and dEg/dT = − 4.4 × 10−4 eV/K was established, postulating linear temperature dependence of Eg by fitting the temperature dependent Absorption coefficient at the band Edge αg(T) = 6600 – 4T (K) (cm−1).
-
The Absorption Edge in p-type Hg1-xCdxTe (x 0.2)
Solid State Communications, 1991Co-Authors: Z. Kučera, Pavel Hlídek, P. Höschl, V. Koubele, M. ZváraAbstract:Abstract The optical Absorption Edge of the low concentration p-type single crystals Hg 1− x Cd x Te with composition x ∼ 0.2 was investigated in the temperature range from 5 K to 300 K. The shape of the Absorption Edge depends strongly on the quality of the crystals. For the high-quality samples, two contributions with different slopes and with different temperature evolutions are resolved on the Absorption curve.
John B. Warren - One of the best experts on this subject based on the ideXlab platform.
-
Biological calcium Absorption Edge imaging using monochromatic synchrotron radiation.
Ultramicroscopy, 1991Co-Authors: B. J. Panessa-warren, G.t. Tortora, R.l. Stears, John B. WarrenAbstract:Soft X-ray contact Absorption Edge images of unfixed, unstained biological specimens were made using monochromatic synchrotron radiation. X-ray contact replicas of unfixed, hydrated biological specimens at the nitrogen Absorption Edge and above and below the CaLIII Absorption Edge were compared to comparative conventional morphological and elemental high-resolution imaging methods (scanning and transmission electron microscopy, TEM-histochemistry and TEM-X-ray microanalysis). Soft X-ray Absorption Edge images made above the calcium Absorption Edge clearly revealed morphological detail and identified regions ladened with calcium as verified by TEM histochemistry of identical spores. Similarly, nitrogen Absorption Edge images identified residual nitrogenous material in the spore resuspension medium, and non-viable spores with nitrogen loss due to protoplast disaggregation.
M. Bugar - One of the best experts on this subject based on the ideXlab platform.
-
High temperature optical Absorption Edge of CdTe single crystal
Journal of Applied Physics, 2014Co-Authors: Eduard Belas, S. Uxa, Roman Grill, Pavel Hlídek, L. Šedivý, M. BugarAbstract:The optical Absorption Edge of bulk CdTe single crystal was measured by infrared transmission under saturated Cd pressure in the temperature interval 295–1223 K. The Absorption coefficient was directly determined up to the value of 100 cm−1. For higher values, it was estimated by extrapolating the spectra according to the Urbach exponential rule. It was observed that the common temperature-independent intersection of extrapolated Urbach Absorption Edge, the “Urbach focus,” does not exist in CdTe. The temperature dependence of band-gap energy Eg defined by Eg(300 K) = 1.518 eV and dEg/dT = − 4.4 × 10−4 eV/K was established, postulating linear temperature dependence of Eg by fitting the temperature dependent Absorption coefficient at the band Edge αg(T) = 6600 – 4T (K) (cm−1).
