Dynamics of Change in Electrical Conductivity of Ion Irradiated Amorphous Silicon.

1991 ◽  
Vol 235 ◽  
Author(s):  
Jung H. Shin ◽  
J. S. Im ◽  
H. A. Atwater
Keyword(s):  
Electrical Conductivity ◽  
Amorphous Silicon ◽  
Ion Irradiation ◽  
Activation Energies ◽  
Temperature Range

ABSTRACTThe dynamics of relaxation of amorphous silicon after unrelaxation (creation of defects) by irradiation with 600 KeV Kr++ ions is investigated using the changes in electrical conductivity of amorphous silicon. By measuring the conductivity of such unrelaxed amorphous silicon after being partially relaxed by isochronal anneals in a temperature range from 383 to 873° K, it is shown that conductivity of amorphous silicon decreases monotonically by up to 3 orders of magnitude as it relaxes; i.e. that conductivity is a measure of the degree of relaxation. Furthermore, it is found that such change in conductivity can be completely reversed by a subsequent unrelaxation with ion irradiation. Continuous in situ measurements of conductivity of amorphous silicon before, during and immediately after irradiation in a temperature range from 77 to 573° K show that relaxation occurs even at 77°K. Finally, the relaxation of amorphous silicon thus measured is linear when plotted against ln(t), a behavior that is characteristic of relaxation with a spectrum of activation energies.

scholarly journals Preparation and Thermoelectric Properties of Graphite/poly(3,4-ethyenedioxythiophene) Nanocomposites

Energies ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 2849 ◽  
Author(s):  
Yong Du ◽  
Haixia Li ◽  
Xuechen Jia ◽  
Yunchen Dou ◽  
Jiayue Xu ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Seebeck Coefficient ◽  
Thermoelectric Properties ◽  
Power Factor ◽  
Oxidative Polymerization ◽  
Polymerization Process ◽  
Measurement Temperature ◽  
Temperature Range ◽  
Different Content

Graphite/poly(3,4-ethyenedioxythiophene) (PEDOT) nanocomposites were prepared by an in-situ oxidative polymerization process. The electrical conductivity and Seebeck coefficient of the graphite/PEDOT nanocomposites with different content of graphite were measured in the temperature range from 300 K to 380 K. The results show that as the content of graphite increased from 0 to 37.2 wt %, the electrical conductivity of the nanocomposites increased sharply from 3.6 S/cm to 80.1 S/cm, while the Seebeck coefficient kept almost the same value (in the range between 12.0 μV/K to 15.1 μV/K) at 300 K, which lead to an increased power factor. The Seebeck coefficient of the nanocomposites increased from 300 K to 380 K, while the electrical conductivity did not substantially depend on the measurement temperature. As a result, a power factor of 3.2 μWm−1 K−2 at 380 K was obtained for the nanocomposites with 37.2 wt % graphite.

scholarly journals Effect of processing parameters on in situ screen printing-assisted synthesis and electrical properties of Ti3SiC2-based structures

2021 ◽  
Vol 10 (1) ◽  
pp. 129-138
Author(s):  
Mylena Lorenz ◽  
Nahum Travitzky ◽  
Carlos R. Rambo
Keyword(s):  
Electrical Conductivity ◽  
Surface Roughness ◽  
Electrical Properties ◽  
Dwell Time ◽  
Screen Printing ◽  
Processing Parameters ◽  
Powder Mixtures ◽  
Temperature Range ◽  
Screen Printed

AbstractThis work reports on the development of pastes containing Ti, TiC, Si, and C elementary powders for in situ synthesis of Ti3SiC2 via screen printing. Four paste compositions were manufactured using two powder mixtures (Ti/Si/C and Ti/TiC/Si/C) with different stoichiometry. The pastes were screen printed onto Al2O3 substrates and sintered at 1400 ℃ in argon varying the dwell time from 1 to 5 h. The printed pastes containing TiC and excess of Si exhibited the lowest surface roughness and after 5 h sintering comprised of Ti3SiC2 as the majority phase. The electrical conductivity of this sample was found to range from 4.63×104 to 2.57×105 S·m–1 in a temperature range of 25–400 ℃.

scholarly journals Электропроводность монокристаллов MnGaInSе-=SUB=-4-=/SUB=- на переменном токе

2020 ◽  
Vol 46 (11) ◽  
pp. 19
Author(s):  
Н.Н. Нифтиев ◽  
Ф.М. Мамедов ◽  
М.Б. Мурадов
Keyword(s):  
Electrical Conductivity ◽  
Single Crystal ◽  
Frequency Dependence ◽  
Electric Current ◽  
Single Crystals ◽  
Activation Energies ◽  
Temperature Range ◽  
Temperature Dependences ◽  
Alternating Electric Current

The results of studying the frequency and temperature dependences of the electrical conductivity of MnGaInSe4 single crystals on alternating electric current are presented. It was found that in the temperature range of 295.5–360 K at frequencies of 2•104–106 Hz, the regularity σ ∼ fS (0.1≤ s≤1.0) holds for electrical conductivity. It is shown that in the MnGaInSe4 single crystal the frequency dependence of electrical conductivity can be explained using the multiplet model, and the conductivity in these single crystals is characterized by a band-hop mechanism. Based on the dependences log σ ∼ 103/T, the activation energies are determined.

scholarly journals Thermal Conductivity of Cu-Cr-Zr-Ti Alloy in the Temperature Range of 300–873 K

2012 ◽  
Vol 2012 ◽  
pp. 1-4 ◽  
Author(s):  
S. Chenna Krishna ◽  
N. Supriya ◽  
Abhay K. Jha ◽  
Bhanu Pant ◽  
S. C. Sharma ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Thermal Conductivity ◽  
Electrical Conductivity ◽  
Room Temperature ◽  
Ofhc Copper ◽  
Ti Alloy ◽  
Phonon Thermal Conductivity ◽  
Temperature Range ◽  
Transmission Electron

In the present investigation, thermal conductivity of Cu-Cr-Zr-Ti alloy was determined as the product of the specific heat (), thermal diffusivity (), and density () in the temperature range of 300–873 K. The experimental results showed that the thermal conductivity of the alloy increased with increase in temperature up to 873 K and the data was accurately modeled by a linear equation. For comparison, thermal conductivity was also evaluated for OFHC copper in the same temperature range. The results obtained were discussed using electrical conductivity and hardness measurements made at room temperature. Transmission electron microscopy (TEM) was done to understand the microstructural changes occurring in the sample after the test. Wiedemann-Franz-Lorenz law was employed for calculating electronic and phonon thermal conductivity using electrical conductivity. On the basis of studies conducted it was deduced that in situ aging may be one of the reasons for the increase in thermal conductivity with temperature for Cu-Cr-Zr-Ti alloy.

scholarly journals Synthesis, Structure and NH3 Sorption Properties of Mixed Mg1-xMnx(NH3)6Cl2 Ammines

Energies ◽  
2020 ◽  
Vol 13 (11) ◽  
pp. 2746 ◽  
Author(s):  
Perizat Berdiyeva ◽  
Anastasiia Karabanova ◽  
Jakob B. Grinderslev ◽  
Rune E. Johnsen ◽  
Didier Blanchard ◽  
...  
Keyword(s):  
Thermal Analyses ◽  
Activation Energies ◽  
Metal Halide ◽  
Sorption Properties ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Mixed Metal ◽  
Temperature Range

This paper describes the synthesis, crystal structure, and NH3 sorption properties of Mg1-xMnx(NH3)6Cl2 (x = 0–1) mixed metal halide ammines, with reversible NH3 storage capacity in the temperature range 20–350 °C. The stoichiometry (x) dependent NH3 desorption temperatures were monitored using in situ synchrotron radiation powder X-ray diffraction, thermogravimetric analysis, and differential scanning calorimetry. The thermal analyses reveal that the NH3 release temperatures decrease in the mixed metal halide ammines in comparison to pure Mg(NH3)6Cl2, approaching the values of Mn(NH3)6Cl2. Desorption occurs in three steps of four, one and one NH3 moles, with the corresponding activation energies of 54.8 kJ⋅mol-1, 73.2 kJ⋅mol-1 and 91.0 kJ⋅mol-1 in Mg0.5Mn0.5(NH3)6Cl2, which is significantly lower than the NH3 release activation energies of Mg(NH3)6Cl2 (Ea = 60.8 kJ⋅mol-1, 74.8 kJ⋅mol-1 and 91.8 kJ⋅mol-1). This work shows that Mg1-xMnx(NH3)yCl2 (x = 0 to 1, y = 0 to 6) is stable within the investigated temperature range (20–350 °C) and also upon NH3 cycling.

Ion Irradiation Effects in Synthetic Garnets Incorporating Actinides

2002 ◽  
Vol 713 ◽  
Author(s):  
Satoshi Utsunomiya ◽  
Lu-Min Wang ◽  
Sergey Yudintsev ◽  
Rodney C. Ewing
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Ion Irradiation ◽  
Atomic Mass ◽  
Irradiation Effects ◽  
Temperature Range ◽  
Transmission Electron

ABSTRACTRadiation durability of garnet [A3B2(XO4)3; Ia3d; Z=8] has been examined by 1.0 MeV Kr2+ irradiation with in situ transmission electron microscopy over the temperature range of 50 to 1070 K. The targets were five synthetic garnets incorporating various contents of actinides and andradite, Ca3Fe2Si3O12. The synthetic garnets were silicates (N series) and ferrate-aluminate series (G series).The critical amorphization temperatures (Tc), above which amorphization does not occur, were determined to be 1050 K for N77, 1130 K for N56, 1100 K for G3, 890 K for G4 and 1030 K for andradite. Tc of the synthetic garnets increased as the average atomic mass of the garnet increased. The maximum transferred energy by ballistic interaction was positively correlated to the atomic mass. The larger cascade size that formed due to the larger Emax might lead to the higher Tc.

Electrical transport in gadolinium iron garnet (GdIG)

1979 ◽  
Vol 57 (8) ◽  
pp. 1204-1208 ◽  
Author(s):  
Vijayee Ram Yadav ◽  
H. B. Lal
Keyword(s):  
Electrical Conductivity ◽  
Curie Temperature ◽  
Thermoelectric Power ◽  
Electrical Transport ◽  
Activation Energies ◽  
Electric Conduction ◽  
Temperature Range ◽  
Iron Garnet ◽  
Band Conduction

Thermoelectric power [Formula: see text] and electrical conductivity (σ) of Gd3Fe5O12 (gadolinium iron garnet GdIG) have been reported in the temperature range 500 to 1200 K. [Formula: see text] remains almost constant between 600 and 1100 K but it increases with decrease of temperature in accordance with the relation[Formula: see text]Conductivity changes by a factor of five near the ferrimagnetic Curie temperature (Te = 564 K). The log σ vs. T−1 curve also has a break at 900 K. Besides this jump and break the log σ vs. T−1 plot is linear and slopes of these lines correspond to activation energies of 0.55 eV for T < 560 K, 0.75 eV for the temperature range 575–900 K, and 0.92 eV between 900 and 1200 K. It has been concluded that electric conduction up to 1200 K in this compound is extrinsic. Between 575 and 1200 K it is due to hopping of holes from Fe4+ to Fe3+ sites and below 560 K it is due to the band conduction of holes in the valence (O2−, 2p) band.

Effets of surfaces on precipitate morphology in irradiated thin foils

1978 ◽  
Vol 36 (1) ◽  
pp. 654-655
Author(s):  
D.I. Potter ◽  
A. Taylor
Keyword(s):  
Ion Irradiation ◽  
Dark Field Image ◽  
Thin Foil ◽  
Dark Field ◽  
Al Alloy ◽  
Bright Field Image ◽  
Dislocation Loops ◽  
Precipitate Morphology ◽  
Thin Foils

Thermal aging of Ni-12.8 at. % A1 and Ni-12.7 at. % Si produces spatially homogeneous dispersions of cuboidal γ'-Ni3Al or Ni3Si precipitate particles arrayed in the Ni solid solution. We have used 3.5-MeV 58Ni+ ion irradiation to examine the effect of irradiation during precipitation on precipitate morphology and distribution. The nearness of free surfaces produced unusual morphologies in foils thinned prior to irradiation. These thin-foil effects will be important during in-situ investigations of precipitation in the HVEM. The thin foil results can be interpreted in terms of observations from bulk irradiations which are described first.Figure 1a is a dark field image of the γ' precipitate 5000 Å beneath the surface(∿1200 Å short of peak damage) of the Ni-Al alloy irradiated in bulk form. The inhomogeneous spatial distribution of γ' results from the presence of voids and dislocation loops which can be seen in the bright field image of the same area, Fig. 1b.

Electron and ion irradiation-induced dissolution of mechanical twins in the intermetalic U3Si: An in situ HVEM study

1989 ◽  
Vol 47 ◽  
pp. 652-653
Author(s):  
Charles W. Allen ◽  
Robert C. Birtcher
Keyword(s):  
Elevated Temperatures ◽  
Ion Irradiation ◽  
Ion Beam ◽  
National Laboratory ◽  
Argonne National Laboratory ◽  
Heavy Ion ◽  
High Energy ◽  
Mechanical Twinning ◽  
In Situ Experiments

The uranium silicides, including U3Si, are under study as candidate low enrichment nuclear fuels. Ion beam simulations of the in-reactor behavior of such materials are performed because a similar damage structure can be produced in hours by energetic heavy ions which requires years in actual reactor tests. This contribution treats one aspect of the microstructural behavior of U3Si under high energy electron irradiation and low dose energetic heavy ion irradiation and is based on in situ experiments, performed at the HVEM-Tandem User Facility at Argonne National Laboratory. This Facility interfaces a 2 MV Tandem ion accelerator and a 0.6 MV ion implanter to a 1.2 MeV AEI high voltage electron microscope, which allows a wide variety of in situ ion beam experiments to be performed with simultaneous irradiation and electron microscopy or diffraction.At elevated temperatures, U3Si exhibits the ordered AuCu3 structure. On cooling below 1058 K, the intermetallic transforms, evidently martensitically, to a body-centered tetragonal structure (alternatively, the structure may be described as face-centered tetragonal, which would be fcc except for a 1 pet tetragonal distortion). Mechanical twinning accompanies the transformation; however, diferences between electron diffraction patterns from twinned and non-twinned martensite plates could not be distinguished.

The reaction of amorphous Ni-Nb films with Si in the presence of a native SiO2 layer

1990 ◽  
Vol 48 (4) ◽  
pp. 664-665
Author(s):  
N. Rozhanski ◽  
A. Barg
Keyword(s):  
High Temperature ◽  
Crystallization Temperature ◽  
Diffusion Barriers ◽  
Sio2 Layer ◽  
Si Substrate ◽  
Cross Sectional ◽  
Plan View ◽  
Temperature Range ◽  
Sputter Deposited

Amorphous Ni-Nb alloys are of potential interest as diffusion barriers for high temperature metallization for VLSI. In the present work amorphous Ni-Nb films were sputter deposited on Si(100) and their interaction with a substrate was studied in the temperature range (200-700)°C. The crystallization of films was observed on the plan-view specimens heated in-situ in Philips-400ST microscope. Cross-sectional objects were prepared to study the structure of interfaces.The crystallization temperature of Ni5 0 Ni5 0 and Ni8 0 Nb2 0 films was found to be equal to 675°C and 525°C correspondingly. The crystallization of Ni5 0 Ni5 0 films is followed by the formation of Ni6Nb7 and Ni3Nb nucleus. Ni8 0Nb2 0 films crystallise with the formation of Ni and Ni3Nb crystals. No interaction of both films with Si substrate was observed on plan-view specimens up to 700°C, that is due to the barrier action of the native SiO2 layer.

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