The Influence of Thermal Treatment on Monocrystalline CZT and Tellurium Inclusions

2015 ◽  
Vol 1792 ◽  
Author(s):  
Jonathan Lassiter ◽  
Charles Payton ◽  
Maxx Jackson ◽  
Samuel Uba ◽  
Claudiu Muntele ◽  
...  
Keyword(s):  
Electrical Properties ◽  
Thermal Treatment ◽  
Structural Changes ◽  
Radiation Detector ◽  
Radiation Detectors ◽  
Thermal Treatments ◽  
Annealing Conditions ◽  
Optimal Annealing Temperature ◽  
Before And After ◽  
Temperature Radiation

ABSTRACTCadmium Zinc Telluride (CZT), considered as a viable material for use in room temperature radiation detectors, has an undesired presence of tellurium inclusions in the bulk. Thermal treatment, in the form of annealing, has been utilized to test the viability of refining CZT into better detector material, either by the elimination of the tellurium inclusions or by the migration of the inclusions under a temperature gradient, but usually with a deterioration of electrical properties. We took infrared micrographs and current voltage (IV) characteristics of CZT samples prior to thermal treatment. We carried out 24-hour thermal treatments with a range of temperature from 100°C to 700°C to determine an optimal annealing temperature and to verify changes in the sizes, morphologies, and locations of the tellurium inclusions on the surfaces and within the crystal bulk of the CZT. The IV curves and resistivities prior to and after thermal treatments were compared, as were the infrared micrographs before and after annealing. Also, the changes in electrical properties of the samples with annealing conditions were compared against structural changes monitored at the same steps during the annealing process, in order to understand the effects of the thermal annealing to the radiation detector properties of the material. Correlations between the shape, size and position of inclusions and electrical properties of the material were attempted.

XRD investigation of thermal degradation of some gamma-irradiated polyethylene terephthalate samples

2019 ◽  
Vol 33 (12) ◽  
pp. 1950111 ◽  
Author(s):  
Mihai Todica ◽  
Zoltan Kovacs-Krauss ◽  
Carmen Niculaescu ◽  
Marieta Mureşan-Pop
Keyword(s):  
Thermal Treatment ◽  
Polyethylene Terephthalate ◽  
Structural Changes ◽  
Diffraction Method ◽  
Resonance Spectroscopy ◽  
X Ray Diffraction ◽  
X Ray ◽  
Before And After ◽  
Gamma Irradiated ◽  
Different Doses

The modification of local structure of some commercial polyethylene terephthalate (PET) samples, gamma irradiated at different doses, was investigated by X-ray diffraction method before and after thermal treatment. Before the thermal treatment, the samples exposed to different doses of gamma radiations, does not show noticeable structural changes. However, the gamma exposure affects the thermal behavior of samples submitted to melting–cooling process. These modifications have been highlighted by X-ray diffraction, and confirmed also by thermal analysis and electron spin resonance spectroscopy.

The Effect of Rapid Thermal Treatment on the Structural and Optoelectronic Properties of Epitaxial Gaas on Si Grown With or Without Ge Intermediate Layers

1987 ◽  
Vol 92 ◽  
Author(s):  
El-Hang Lee ◽  
M.Abdul Awal ◽  
E. Y. Chan ◽  
R. L. Opila ◽  
D. C. Jacobson ◽  
...  
Keyword(s):  
Electrical Properties ◽  
Thermal Treatment ◽  
Intermediate Layer ◽  
Optoelectronic Properties ◽  
Gaas On Si ◽  
Intermediate Layers ◽  
Structural And Electrical Properties ◽  
Before And After ◽  
Structural And Optoelectronic Properties ◽  
Raman Characterization

ABSTRACTCharacteristics of MOCVD GaAs grown on Si are compared before and after a rapid thermal treatment. The GaAs-on-Si samples were prepared both with and without a Ge intermediate layer, which is used to accomodate mismatches of lattice, thermal and chemical origin between GaAs and Si. Structural, interfacial, chemical, and electrical changes have been examined. RBS and Raman characterization showed improvement of GaAs crystallinity after RTA. In most cases, the interfaces were found to become sharper after RTA, but chemical interdiffusion was observed to cause some effect on the structural and electrical properties. For gold-contacted GaAs, RTA seems to degrade the electrical and optoelectronic properties via gold interdiffusion into GaAs. Comparative studies of the GaAs/Si and GaAs/Ge/Si samples suggests that the two respond somewhat differently to RTA.

Negative Capacitance Phenomena in CZT Room Temperature Radiation Detectors

2005 ◽  
Vol 480-481 ◽  
pp. 399-404
Author(s):  
Mahmoud A. Hassan
Keyword(s):  
Bias Voltage ◽  
Room Temperature ◽  
Bulk Material ◽  
Radiation Detector ◽  
Radiation Detectors ◽  
Negative Capacitance ◽  
Low Frequencies ◽  
Temperature Radiation ◽  
Czt Detectors ◽  
Small Voltage

CdZnTe , Cadmium zinc telluride (CZT) is an interesting room temperature radiation detector. This research paper is reporting a negative capacitance behavior of CZT detectors at bias voltages around 60V. Initially at 0V, the CZT capacitance is positive and decreases with bias voltage increase. At around 60V, the measured capacitance approaches zero, then with small voltage increase , capacitance value reverses sign and starts to increase in the negative direction with increasing bias voltage . This effect is stable at 100 kHz. The behavior of low and other quality detectors can differ, low quality detectors can show negative capacitance at low bias voltages and low frequencies. The initial explanation of this phenomena is due to non-uniform distribution of impurities inside the bulk material.

scholarly journals Structural changes of Cr-beidellite treated up to 1350 °C in oxygen or nitrogen atmospheres

Cerâmica ◽  
2018 ◽  
Vol 64 (369) ◽  
pp. 64-68
Author(s):  
H. S. Santos ◽  
A. M. Cesio ◽  
M. Gauna ◽  
V. F. Justo ◽  
C. Volzone
Keyword(s):  
Thermal Analysis ◽  
High Temperature ◽  
Thermal Treatment ◽  
Structural Changes ◽  
Pillared Clay ◽  
Nitrogen Atmosphere ◽  
Thermal Treatments ◽  
X Ray Diffraction ◽  
X Ray ◽  
Mineralogical Phases

Abstract Beidellite clay mineral after intercalation of OH-Cr(III) species were thermally analyzed up to 1350 °C in oxygen and nitrogen atmospheres. OH-Cr-beidellite can be used as a pillared clay precursor for catalysis or as adsorbent applications. However, in this paper beidellite enriched in chromium were analyzed at different thermal treatments up to high temperature for evaluating structural changes for possible future ceramic applications. The structural changes were followed by thermal analysis and X-ray diffraction. The thermal treatment of OH-Cr-beidellite in oxygen and nitrogen atmospheres developed different mineralogical phases up to 1050 °C, but at higher temperatures, the same phases were developed in both atmosphere treatments. Eskolaite phase (Cr2O3) appeared in the sample after heating at 400 °C in oxygen atmosphere, whereas grimaldite (CrO-OH) in nitrogen atmosphere, maintaining the starting phases. At 1000 °C the raw clay minerals disappeared, as it is knew. At 1050 °C in nitrogen atmosphere, grimaldite was absent and eskolaite appeared. At 1350 °C in the samples calcined in both atmospheres, quartz, cristobalite and mullite as the main phases and in lower contents aluminum oxide and aluminum-chromium oxide [(Al,Cr)2O3] were present.

scholarly journals Passivation of Semiconductor Surfaces for Improved Radiation Detectors: X-Ray Photoemission Analysis

2007 ◽  
Vol 1038 ◽  
Author(s):  
Art J Nelson ◽  
A M Conway ◽  
C E Reinhardt ◽  
J L Ferreira ◽  
R J Nikolic ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Photoelectron Spectroscopy ◽  
Surface Passivation ◽  
Radiation Detector ◽  
Radiation Detectors ◽  
X Ray ◽  
Semiconductor Crystals ◽  
Chemically Treated ◽  
Before And After ◽  
Metal Overlayers

AbstractSurface passivation of device-grade radiation detector materials was investigated using x-ray photoelectron spectroscopy in combination with transport property measurements before and after various chemical treatments. Specifically Br-MeOH (2% Br), KOH with NH4F/H2O2 and NH4OH solutions were used to etch, reduce and oxidize the surface of Cd(1-x)ZnxTe semiconductor crystals. Scanning electron microscopy was used to evaluate the resultant microscopic surface morphology. Angle-resolved high-resolution photoemission measurements on the valence band electronic structure and core lines were used to evaluate the surface chemistry of the chemically treated surfaces. Metal overlayers were then deposited on these chemically treated surfaces and the I-V characteristics measured. The measurements were correlated to understand the effect of interface chemistry on the electronic structure at these interfaces with the goal of optimizing the Schottky barrier height for improved radiation detector devices.

Purification of HgI2 Crystals from Physical Vapor Transport for Application as Radiation Detectors

2012 ◽  
Vol 586 ◽  
pp. 156-160 ◽  
Author(s):  
João F. Trencher Martins ◽  
Robinson A. dos Santos ◽  
Fabio E. da Costa ◽  
Carlos H. de Mesquita ◽  
Margarida M. Hamada
Keyword(s):  
Impurity Concentration ◽  
Radiation Detector ◽  
Radiation Detectors ◽  
Vapor Transport ◽  
Future Application ◽  
Physical Vapor Transport ◽  
Semiconductor Detectors ◽  
Trace Impurities ◽  
Detector Performance ◽  
Temperature Radiation

The establishment of a technique for mercury iodide (HgI2) purification and crystal growth is described, aiming this crystal future application as room temperature radiation semiconductor detectors. Repeated Physical Vapor Transport (PVT) technique was studied for purification and growth of the crystal. To evaluate the purification efficiency, measurements of the impurity concentration were made after each growth, analyzing the trace impurities. A significant decrease of the impurity concentration, resulting from the purification number, was observed. A significant improvement in the HgI2 radiation detector performance was achieved for purer crystals, growing the crystal twice by the PVT technique.

Optical Studies of the Internal Electric Field Distributions of CdZnTe Detectors Under Bias Conditions

1997 ◽  
Vol 487 ◽  
Author(s):  
H. W. Yao ◽  
R. J. Anderson ◽  
R. B. James ◽  
R. W. Olsen
Keyword(s):  
Electric Field ◽  
Radiation Detector ◽  
Radiation Detectors ◽  
Uniform Electric Field ◽  
Internal Electric Field ◽  
Field Distributions ◽  
Intensity Changes ◽  
Temperature Radiation ◽  
Cdznte Detectors ◽  
Czt Detectors

AbstractThe internal electric field distributions of the CdZnTe (CZT) detectors under bias were characterized by optical polarized transmission at a 952 nm illumination utilizing the Pockels electro-optic effect. Two-dimensional (2D) images mapping the internal electrical field intensity changes were obtained to study the performance of CZT room-temperature radiation detectors. Planar and a P-I-N structured CZT detectors were investigated under different operating bias voltages. Analysis of optical profiles from a planar single crystal detector provides a quantitative nondestructive description of the electric field or voltage distributions inside a radiation detector. The P-I-N structured CZT detector showed a nearly uniform electric field in a width which varied with the operating bias voltage. An energyband model of a semiconductor junction with a depletion layer was employed to understand the results.

scholarly journals Influence of reduction conditions of NiO on its mechanical and electrical properties

2016 ◽  
Vol 6 (1) ◽  
pp. 113 ◽  
Author(s):  
Yehor Brodnikovskyi ◽  
Bogdan Vasyliv ◽  
Viktoriya Podhurska ◽  
Mariusz Andrzejczuk ◽  
Nikkia McDonald ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Electrical Properties ◽  
Structural Changes ◽  
Reduction Stage ◽  
Mechanical And Electrical Properties ◽  
Before And After ◽  
Mechanical Durability ◽  
And Performance ◽  
The Impact ◽  
Volume Decrease

<p class="PaperAbstract"><span lang="EN-GB">Yttria stabilized zirconia with a nickel catalyst (Ni-YSZ) is the most developed, widely used cermet anode for manufacturing Solid Oxide Fuel Cells (SOFCs). Its electro-catalytic properties, mechanical durability and performance stability in hydrogen-rich environ­ments makes it the state of the art fuel electrode for SOFCs. During the reduction stage in initial SOFC operation, the virgin anode material, a NiO-YSZ mixture, is reduced to Ni-YSZ. The volume decrease associated with the change from NiO-YSZ to Ni-YSZ creates voids and causes structural changes, which can influence the physical properties of the anode. In this work, the structural, mechanical and electrical properties of NiO samples before and after reduction in pure H<sub>2</sub> and a mixture of 5 vol. % H<sub>2</sub>-Ar were studied. The NiO to Ni phase transformations that occur in the anode under reducing and Reduction-Oxidation (RedOx) cycling conditions and the impact on cell microstruc­ture, strength and electrical conductivity have been examined. Results show that the RedOx treatment of the NiO samples influence on their properties controversially, due to structural transfor­mation (formation of large amount of fine pores) of the reduced Ni. It strengthened the treated samples yielding the highest mechanical strength values of 25.7 MPa, but from another side it is resulting in lowest electrical conductivity value of 1.9×10<sup>5</sup> S m<sup>-1</sup> among all reduced samples. The results of this investigation shows that reduction conditions of NiO is a powerful tool for influence on properties of the anode substrate.</span></p>

scholarly journals Influence of the crystallization thermal treatment on the structural and electrical properties of PZT thin films

2004 ◽  
Vol 7 (2) ◽  
pp. 363-367 ◽  
Author(s):  
Antonio Leondino Bacichetti Junior ◽  
Manuel Henrique Lente ◽  
Ricardo Gonçalves Mendes ◽  
Pedro Iris Paulin Filho ◽  
José Antonio Eiras
Keyword(s):  
Thin Films ◽  
Electrical Properties ◽  
Thermal Treatment ◽  
Pzt Thin Films ◽  
Structural And Electrical Properties

scholarly journals A multilevel investigation supported by multivariate analysis for tomato product formulation

2021 ◽  
Author(s):  
Fatma Boukid ◽  
Elena Curti ◽  
Agoura Diantom ◽  
Eleonora Carini ◽  
Elena Vittadini
Keyword(s):  
Thermal Treatment ◽  
Color Change ◽  
Water Molecules ◽  
Thermal Treatments ◽  
Industrial Processing ◽  
H Nmr ◽  
Mobile Populations ◽  
Product Formulation ◽  
Tomato Product ◽  
The Impact

AbstractIndustrial processing of tomato includes its cutting and mincing, thermal treatments, and the addition of ingredients, which might induce changes in physicochemical properties of the final products. In this frame, the impact of texturing/thickening [xanthan gum (X) or potato fiber (F)] on the macroscopic, mesoscopic and molecular properties of tomato double concentrate (TDC) was investigated to determine if F can efficiently substitute X, in association with small solutes (sugar and salt) and thermal treatment (cold and hot). At a macroscopic level, multivariate statistics (MANOVA) underlined that color change (ΔE) was increased by X and F addition contrary to heating and the addition of salt and sugar. MANOVA revealed that texture was greatly enhanced through the use of F over X. 1H NMR molecular mobility changes were more controlled by texturing agents (F and X) than thermal treatment and small solutes. Particularly F increased the more rigid population indicating stronger interaction with water molecules resulting in shear-thinning flow. However, adding X contributed into the increase of the dynamic and mobile populations. Therefore, F can be a valid “clean label” substitute of X in modulating tomato products properties.

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