Study on Low Temperature Conduction Mechanism of Al Doped ZnO/SiO2/ P-Si Heterojunction

2021 ◽  
Vol 904 ◽  
pp. 363-368
Author(s):  
Xiao Yan Zhou ◽  
Bang Sheng Yin
Keyword(s):  
Activation Energy ◽  
Impedance Spectroscopy ◽  
Low Temperature ◽  
Grain Boundaries ◽  
Ac Conductivity ◽  
Spray Pyrolysis Method ◽  
Temperature Conductivity ◽  
Calculated Activation Energy ◽  
Doped Zno ◽  
Temperature Conduction

The 3 at% Al doped ZnO thin films were deposited on p-Si substrate with a native SiO2 layer by spray pyrolysis method. Low temperature conduction behaviors were studied by analysis of impedance spectroscopy and low temperature ac conductivity. The results of impedance spectroscopy showed that the grain boundaries contributed to the resistivity of Al doped ZnO/SiO2/p-Si heterojunction. The calculated activation energy was 0.073 eV for grain boundaries. The equivalent circuit to demonstrate the electrical properties of Al doped ZnO/SiO2/p-Si heterojunction was a series connection of two parallel combination circuits of a resistor and a universal capacitor. Low temperature ac conductivity measurements indicated that the conductivity increased with temperature. Low temperature conductivity mechanism was electron conductivity, and the activation energy was 0.086 eV.

Grain growth behavior of a nanostructured 5083 Al–Mg alloy

2001 ◽  
Vol 16 (4) ◽  
pp. 938-944 ◽  
Author(s):  
V. L. Tellkamp ◽  
S. Dallek ◽  
D. Cheng ◽  
E. J. Lavernia
Keyword(s):  
Activation Energy ◽  
Stress Relaxation ◽  
Low Temperature ◽  
Grain Boundaries ◽  
Relaxation Process ◽  
Grain Growth ◽  
Alloy Powder ◽  
Growth Behavior ◽  
Mg Alloy ◽  
Grain Growth Behavior

A nanostructured 5083 Al–Mg alloy powder was subjected to various thermal heat treatments in an attempt to understand the fundamental mechanisms of recovery, recrystallization and grain growth as they apply to nanostructured materials. A low-temperature stress relaxation process associated with reordering of the grain boundaries was found to occur at 158 °C. A bimodal restructuring of the grains occurred at 307 °C for the unconstrained grains and 381 °C for the constrained grains. An approximate activation energy of 5.6 kJ/mol was found for the metastable nanostructured grains, while an approximate activation energy of 142 kJ/mol was found above the restructuring temperature.

Analysis of defect formation in Nb-doped SrTiO3 by impedance spectroscopy

2001 ◽  
Vol 16 (1) ◽  
pp. 192-196 ◽  
Author(s):  
Seong-Ho Kim ◽  
Jung-Ho Moon ◽  
Jae-Hwan Park ◽  
Jae-Gwan Park ◽  
Yoonho Kim
Keyword(s):  
Activation Energy ◽  
Impedance Spectroscopy ◽  
Grain Boundary ◽  
Single Crystal ◽  
Grain Boundaries ◽  
Thermal Activation ◽  
Oxygen Vacancies ◽  
Defect Formation ◽  
Activation Energies ◽  
Single Grain

The thermal activation energies for conduction of Nb-doped SrTiO3 grains and grain boundaries have been investigated by impedance spectroscopy. First, to observe the effect of electrode/SrTiO3 bulk interface, the varied impedances of SrTiO3 single crystal were measured with temperatures. The activation energy of an electrode/bulk interface was determined to be 1.3 eV, whereas that of bulk was 0.8 eV. When the impedances of Nb-doped SrTiO3 ceramics were measured, it was suggested that the more precise impedance values of a single grain and a single grain to grain junction be obtained using a microelectrode method. The activation energies for a grain, a grain boundary, and an electrode/bulk interface were determined to be about 0.8, 1.3, and 1.5 eV, respectively. From these measured results, it was suggested that the activation energy, 0.8 eV, measured in grain was originated from oxygen vacancies and the activation energy, 1.3 eV, in grain boundary was from strontium vacancies.

AC MEASUREMENTS ON COEVAPORATED GeO2/BaO THIN FILMS

1994 ◽  
Vol 08 (23) ◽  
pp. 1453-1459
Author(s):  
M.Y. NADEEM
Keyword(s):  
Thin Films ◽  
Activation Energy ◽  
Low Temperature ◽  
Temperature Dependence ◽  
Thin Layers ◽  
Hopping Conduction ◽  
Frequency Range ◽  
Temperature Conduction ◽  
Ac Conductance ◽  
Metallic Electrodes

The frequency and temperature dependence of the ac conductance and the capacitance are studied in the frequency range of 1 to 20 kHz for the coevaporated GeO 2/ BaO thin layers sandwiched between Al metallic electrodes. The measurements are undertaken to establish the low temperature conduction in these diode structures as the electronic hopping conduction. The activation energy involved in this mechanism is evaluated.

Properties Of crystalline 3C-SIC Grown From Methyl Trichlorosilane

1994 ◽  
Vol 339 ◽  
Author(s):  
W. J. Moore ◽  
R. Kaplan ◽  
J. A. Freitas ◽  
Y. M. Altaiskii ◽  
V. L. Zuev ◽  
...  
Keyword(s):  
Activation Energy ◽  
Low Temperature ◽  
Effective Mass ◽  
Nitrogen Concentration ◽  
Excitation Spectra ◽  
High Quality ◽  
Temperature Conductivity ◽  
Ir Transmission ◽  
Temperature Electron ◽  
Cubic Silicon Carbide

ABSTRACTCubic silicon carbide grown by thermal decomposition of methyl trichlorosilane in hydrogen has been studied in infrared (IR) transmission, cyclotron resonance (CR), and photoluminescence (PL). Sample characteristics include: The nitrogen concentration, determined from CR and IR can be of the order of 1015 cm-3 or less. Ionized impurity concentrations determined from the linewidths of CR and IR spectra can be less than 7 × 1014 cm-3. Low temperature electron mobilities from CR are near 105 cm2 v-1 s-1. Carrier freeze-out is consistent with either uncompen-sated donors with activation energy near 50 meV or heavily compensated donors with 20 meV activation energy. The latter choice, however, is excluded by the low ionized impurity concentration. These high quality samples show little or no evidence of the apparently shallow (< ∼20 meV) donor which usually dominates the low temperature conductivity of 3C-SiC grown on Si. Nitrogen donor excitation spectra are in excellent agreement with effective mass theory. Only nitrogen donors at 54.2 meV and an unidentified effective-mass donor at 47.8 meV are observed. If material with the characteristics described above can be reliably reproduced then there is substantial expectation that high quality electronic devices based on 3C-SiC can be fabricated.

scholarly journals AC Conductivity and Impedance Properties of 0.65Pb(Mg1/3Nb2/3)O3-0.35PbTiO3Ceramics

2009 ◽  
Vol 2009 ◽  
pp. 1-6 ◽  
Author(s):  
Banarji Behera ◽  
E. B. Araújo ◽  
R. N. Reis ◽  
J. D. S. Guerra
Keyword(s):  
Activation Energy ◽  
Electrical Properties ◽  
Impedance Spectroscopy ◽  
Ac Conductivity ◽  
Electric Permittivity ◽  
Spectroscopy Technique ◽  
Cole Diagram ◽  
Wide Range ◽  
Impedance Spectroscopy Technique ◽  
Grain Bulk

The electrical properties of 0.65Pb(Mg1/3Nb2/3)O3-0.35(PbTiO3) ceramics over a wide range of frequencies (102–106 Hz) and temperatures (30–225∘C) were studied using impedance spectroscopy technique. The impedance and electric permittivity were strongly temperature and frequency dependent. The activation energy, calculated from the temperature dependence of AC conductivity of the ceramics was found to be∼0.5 eV. The relaxation process in the ceramics was found to be of non-Debye type. The nature of Cole-Cole diagram reveals the contribution of grain (bulk) and grain boundary permittivity in the ceramics.

Low temperature conduction and scattering behavior of Ga-doped ZnO

2007 ◽  
Vol 91 (25) ◽  
pp. 252109 ◽  
Author(s):  
Byung Du Ahn ◽  
Sang Hoon Oh ◽  
Hyun Jae Kim ◽  
Myung Hwa Jung ◽  
Young Gun Ko
Keyword(s):  
Low Temperature ◽  
Doped Zno ◽  
Temperature Conduction

scholarly journals The electrical conductivity of stannous sulphide

1945 ◽  
Vol 184 (996) ◽  
pp. 83-101 ◽  
Keyword(s):  
Activation Energy ◽  
Low Temperature ◽  
Present Theory ◽  
Surface Layers ◽  
Considerable Decrease ◽  
Temperature Conductivity ◽  
Full Band ◽  
Ordinary Temperature ◽  
Intrinsic Conduction ◽  
Positive Holes

The conductivity of stannous sulphide has been measured between the ordinary temperature and 400° C, and follows the expression K T = A 1 e - E 1 / kT + A 2 e - E 2 / kT . The low-temperature conductivity has been studied with particular reference to the effect of chemical treatment calculated to change any deviations from ideal stoich iometric composition. Treatment with hydrogen at temperatures below those at which reduction to tin can occur brings about a considerable decrease in conductivity; exposure to oxygen or to hydrogen sulphide restores the conductivity. The low-temperature conductivity is attributable to a stoichiometric excess of non-metal in the lattice, the current being transported by a corresponding number of positive holes. From the rate of diminution or restoration of conductivity, the positive holes must be located in the surface layers of atoms of the crystallites. The changes in conductivity resulting from changes in the stoichiometric defect arise almost entirely through the change in the activation energy of the conduction process, E 1 . Although not considered in the present theory of semiconductors, both E 1 and the electronic mobility are functions of the concentration of conducting centres. The high-temperature conductivity is attributed to the intrinsic conduction of the lattice, and indicates the existence of a conduction band about 1·2 eV above the full band.

scholarly journals Low Temperature Broad Band Dielectric Spectroscopy of Multiferroic Bi6Fe2Ti3O18 Ceramics

2016 ◽  
Vol 61 (3) ◽  
pp. 1447-1452 ◽  
Author(s):  
A. Lisińska-Czekaj ◽  
M. Rerak ◽  
D. Czekaj ◽  
M. Lubina ◽  
B. Garbarz-Glos ◽  
...  
Keyword(s):  
Activation Energy ◽  
Grain Boundaries ◽  
Dielectric Spectroscopy ◽  
Ac Conductivity ◽  
Broad Band ◽  
Relaxation Times ◽  
Dielectric Behavior ◽  
Nyquist Plot ◽  
Chi Square ◽  
Impedance Data

AbstractIn the present research the tool of broadband dielectric spectroscopy was utilized to characterize dielectric behavior of Bi6Fe2Ti3O18(BFTO) Aurivillius-type multiferroic ceramics. Dielectric response of BFTO ceramics was studied in the frequency domain (Δν=0.1Hz – 10MHz) within the temperature range ΔT=-100°C – 200°C. The Kramers-Kronig data validation test was employed to validate the impedance data measurements and it was found that the measured impedance data exhibited good quality justifying further analysis. The residuals were found to be less than 1%, whereas the “chi-square” parameter was within the range χ2~10−7−10−5. Experimental data were analyzed using the circle fit of simple impedance arc plotted in the complex Z”-Z’ plane (Nyquist plot). The total ac conductivity of the grain boundaries was thus revealed and the activation energy of ac conductivity for the grain boundaries was calculated. It was found that activation energy of ac conductivity of grain boundaries changes from EA=0.20eV to EA=0.55eV while temperature rises from T=-100°C up to T=200°C. On the base of maxima of the impedance semicircles (ωmτm=1) the relaxation phenomena were characterized in terms of the temperature dependence of relaxation times and relevant activation energy was calculated (EA=0.55eV).

Pt-Pd Nanoalloy for the Unprecedented Activation of Carbon-Fluorine Bond at Low Temperature

2019 ◽  
Author(s):  
Raghu Nath Dhital ◽  
keigo nomura ◽  
Yoshinori Sato ◽  
Setsiri Haesuwannakij ◽  
Masahiro Ehara ◽  
...  
Keyword(s):  
Activation Energy ◽  
Low Temperature ◽  
Dft Calculations ◽  
Bond Activation ◽  
Mild Conditions ◽  
Selective Transformation ◽  
Rate Determining Step ◽  
Highly Active ◽  
Harsh Conditions ◽  
Reaction Profile

Carbon-Fluorine (C-F) bonds are considered the most inert organic functionality and their selective transformation under mild conditions remains challenging. Herein, we report a highly active Pt-Pd nanoalloy as a robust catalyst for the transformation of C-F bonds into C-H bonds at low temperature, a reaction that often required harsh conditions. The alloying of Pt with Pd is crucial to activate C-F bond. The reaction profile kinetics revealed that the major source of hydrogen in the defluorinated product is the alcoholic proton of 2-propanol, and the rate-determining step is the reduction of the metal upon transfer of the <i>beta</i>-H from 2-propanol. DFT calculations elucidated that the key step is the selective oxidative addition of the O-H bond of 2-propanol to a Pd center prior to C-F bond activation at a Pt site, which crucially reduces the activation energy of the C-F bond. Therefore, both Pt and Pd work independently but synergistically to promote the overall reaction

Sign in / Sign up

Export Citation Format

Share Document