amorphous selenium kinetics

ION IRRADIATION INDUCED CRYSTALLIZATION IN …

Chalcogenide Letters Vol. 4, No. 10, October 2007, p. 115 - 118 ION IRRADIATION INDUCED CRYSTALLIZATION IN AMORPHOUS SELENIUM FILMS I. Ivan*, S. Kokenyesis, A. Csik Institute of Nuclear Research of the Hungarian Academy of Sciences, Bem tér 18/c, 4026

Reduction of Selenite and Detoxification of Elemental ...

The effect of selenite on growth kinetics, the ability of cultures to reduce selenite, and the mechanism of detoxification of selenium were investigated by using Rhodospirillum rubrum.Anoxic photosynthetic cultures were able to completely reduce as much as 1.5 mM selenite, whereas in aerobic cultures a 0.5 mM selenite concentration was only reduced to about 0.375 mM.

Crystallization kinetics of amorphous selenium prepared by ...

The polymorphous crystallization kinetics of a melt-quenched amorphous selenium (a-Se) under pressure was investigated by using a piston–cylinder pressure vessel over a pressure range of 0–1.0 ...

Nonisothermal crystallisation kinetics of amorphous ...

Nonisothermal crystallisation kinetics of amorphous selenium prepared by high-energy ball milling: A comparison with the melt-quenching and thin-film techniques

Amorphous | definition of amorphous by Medical dictionary

amorphous: ( ă-mōr'fŭs ), 1. Without definite shape or visible differentiation in structure. 2. Not crystallized.

Environ. Sci. Technol. 1990, 24, Kinetics of Selenate and ...

Kinetics of Selenate and Selenite Adsorption/Desorption at the Goethite/Water Interface ... amorphous iron oxyhydroxide as a function of pH is es- sentially the same. Balistrieri and Chao (12) and Merrill ... in the scientific literature on the kinetics of selenium re- …

Crystallization kinetics of binary arsenic selenium ...

May 18, 2018· Binary As–Se glasses with different amounts of As content have been prepared and scanned with different heating rates (3 ≤ ψ ≤ 48 K min−1) over temperatures ranging from 300 to 450 K. Both the glass transition temperature (Tgl) and the temperature peak of crystallization (Tpc) increase as a function of As and/or the ψ values. A good correlation between Tgl …

Crystallization of amorphous selenium films. I. Morphology ...

Abstract. We report a study of the morphology and kinetics of crystallization of films of a-Se vapor deposited on mica substrates. Morphological examination was facilitated by the complete dissolution of the amorphous component of the films by CS 2, while the crystalline component was left essentially intact.Crystallization begins (in the temperature range 30-100°C) with the formation and ...

Kinetic Processes in Amorphous Materials Revealed by ...

Kinetic Processes in Amorphous Materials Revealed by Thermal Analysis: Application to Glassy Selenium . by Jiří Málek * and Roman Svoboda. ... This confirms the applicability of the JMA model for the description of non-isothermal crystallization kinetics in selenium glass.

Effect of different sizes of subcritical nuclei on ...

Amorphous modifications of the sulfur group elements contain embryos with different numbers of members of the stable nucleus. During the transformation these embryos form stable nuclei at different rates: the larger the number of members, the more rapid is the formation of a stable nucleus. The nucleation rate depends on the rate of increase of an individual embryo to the critical size and on ...

Kinetic Processes in Amorphous Materials Revealed by ...

This confirms the applicability of the JMA model for the description of non-isothermal crystallization kinetics in selenium glass. Another method to test the validity of this model is the shape analysis of ... In case of amorphous selenium, the position of T e appears to be driven more by viscous flow (in combination with surface tension) at ...

(PDF) Kinetics of the photostructural changes in a-Se films

The kinetics of the photodarkening effect has been studied experimentally for amorphous selenium (a- Se ) layers at room temperature and at an elevated temperature (35 ° C ) close to the glass ...

Effect of tellurium substitution on the crystallization ...

1. Introduction 2. Isothermal transformation kinetics The study of selenium and selenium-tellurium alloys in the amorphous state, so-called chalcogenide glasses, is important in order to understand the phys- ical phenomena occurring in these materials, which are of interest because of their applications in vari- ous optoelectronic devices [1-4].

Dependence of the glass transition temperature on heating ...

Heating rate and composition dependence of the glass transition temperature of a ternary chalcogenide glass. Journal of Materials Science Letters 1994, 13 (2), 77-79. DOI: 10.1007/BF00416803. I S Graham, L Piche, M Grant. .

Amorphous selenium (a-Se) avalanche photodetector for ...

Amorphous selenium (a-Se) avalanche photodetector for applications in Positron Emission Tomography (PET) Master of Science, 2011 Oleksandr Bubon Department of Physics Lakehead University Abstract . Although avalanche amorphous selenium (a-Se) is a very promising photoconductor for a

Kinetics of the photostructural changes in a-Se films ...

The kinetics of the photodarkening effect has been studied experimentally for amorphous selenium (a-Se) layers at room temperature and at an elevated temperature (35 ° C) close to the glass transition. By switching an intense pumping light on and off with a period of 100 s, we have studied the kinetics of both the buildup of photodarkening and its relaxation (recovery).

Measurements of DSC isothermal crystallization kinetics in ...

Measurements of DSC isothermal crystallization kinetics in amorphous selenium bulk samples. In this research, the activation energies of crystallization of amorphous selenium (Se) were studied under isothermal conditions using a differential scanning calorimetric (DSC) technique.

Kinetics of Transformation of Chains in Amorphous Sulphur ...

Jan 11, 2014· The transformation rate of the chains in amorphous sulphur doped with 2, 4 and 6% at. Se was examined by means of a calorimetric method at 298 K. The samples were remelted at T f=443 K. For the description of the results the equation X=1 -cxp[-(kt)z] was used (X-transformation degree, t — time, k and z — constants). Addition of selenium inhibits the transformation and causes a division of ...

Amorphous selenium thin films prepared using chemical …

Amorphous selenium thin films prepared using chemical bath deposition: optimization of the ... kinetics of this material using thermo-analytical techniques. Chand et al [4] have reported on the thermally stimulated discharge current behaviour of native and irradiated a-Se films.

Substrate effects on the crystallization kinetics of ...

Thin Solid Films, 37 (1976) 215-222 CQ Elsevier Sequoia S.A., Lausanne-Printed in Switzerland 215 SUBSTRATE EFFECTS ON THE CRYSTALLIZATION KINETICS OF AMORPHOUS SELENIUM THIN FILMS DAVID D. THORNBURG Xerox Palo Alto Research Center, Palo Alto, Calif. 94304 (U.S.A.) (Received January 23, 1976; accepted February 16, 1976) A thermoanalytical technique has been …

Pressure effect on polymorphous crystallization kinetics ...

Crystallization of amorphous elemental selenium (a-Se) is a typical polymorphous phase transformation forming a stable trigonal crystalline phase (t-Se). Moreover, the volume difference between a-Se and t-Se is relatively large (about 13%), which facilitates the demonstration of the pressure effect on the transformation kinetics.

Crystallization of amorphous selenium films. I. Morphology ...

We report a study of the morphology and kinetics of crystallization of films of a‐Se vapor deposited on mica substrates. Morphological examination was facilitated by the complete dissolution of the amorphous component of the films by CS2, while the crystalline component was left essentially intact. Crystallization begins (in the temperature range 30–100°C) with the formation and radial ...

Electrochemistry of Selenium with Sodium and Lithium ...

Electrochemistry of Selenium with Sodium and Lithium: Kinetics and ... Figure S3. The generating and structure of amorphous Na 0.5 Se phase. (a) The proceeding process of amorphous Na0.5Se for the crystalline NaSe2 phase. (b) Radius distribution function the amorphous phase

amorphous selenium kinetics - breughelsausages.be

Crystallization kinetics of amorphous selenium prepared by ball milling method has been studied using differential scanning calorimetry (DSC). Non-isothermal measurements were performed at different heating rates (3–20 K/min). The activation energy of crystallization was determined by analyzing the data using different kinetic models.

(PDF) Low-temperature steady-state photoconductivity in ...

Low-temperature steady-state photoconductivity in amorphous selenium films Article (PDF Available) in Journal of Optoelectronics and Advanced Materials 7(4) · August 2005 with 28 Reads

Kinetic Processes in Amorphous Materials Revealed by ...

Jul 26, 2019· In case of amorphous selenium, the position of T e appears to be driven more by viscous flow (in combination with surface tension) at low temperatures. Thus, the activation energy determined from the TMA measurements at low q + gets closer to E η.

Anomalous high-pressure behavior of amorphous selenium ...

Sep 09, 2008· The high-pressure behavior of amorphous selenium has been investigated with time-resolved diamond anvil cell synchrotron x-ray diffraction and computed microtomography techniques. A two-step dynamic crystallization process is observed in which the monoclinic phase crystallized from the amorphous selenium and gradually converted to the trigonal phase, thereby explaining previously …

Comparative study of the photodarkening relaxation ...

The relaxation of photodarkening (PD) brought about by above-bandgap and sub-bandgap excitations is studied in a wide temperature range in amorphous selenium (a-Se) films designed for avalanche photodetectors. The experimental results suggest that in contrast to sub-bandgap excitation, above-bandgap excitation does not cause the formation of self-trapped excitons, viz., photoinduced ...

Development of an Amorphous Selenium-Based Photodetector ...

1.2. History of a-Se Based Photoconductive Devices. The first photoconductive drum used for xerography consisted of an amorphous selenium thin film [].In the 1950s, various properties of a-Se, such as photoconductivity and photo generation, were reported [].As it can be imagined from the word "electrophotography (former term for xerography)", the photoconductive properties were soon used ...

Simon Research Group :: Chemical Engineering :: TTU

Nov 13, 2018· Journal Publications . 115. Yung P Koh, Sindee L. Simon, "Enthalpy Recovery of Ultrathin Polystyrene Film Using Flash DSC," Polymer, 143, 40-45 (2018). ... Creep and Creep-Recovery Measurements during Physical Aging of Amorphous Selenium," Journal of Non-Crystalline Solids, 324 (3), 242 - 255 (2003). ... "Reaction Kinetics and TTT Cure Diagrams ...