Atomic Defects in Transition Metal Carbides and SiC Studied by Positron Annihilation

1993 ◽  
Vol 327 ◽  
Author(s):  
A. A. Rempel ◽  
H. -E. Schaefer ◽  
M. Forster ◽  
A.I. Girka
Keyword(s):  
Low Temperature ◽  
Electron Irradiation ◽  
Positron Lifetime ◽  
Group Iv ◽  
Metal Carbides ◽  
Lifetime Measurements ◽  
Transition Metal Carbides ◽  
Before And After ◽  
Radiation Induced ◽  
Subsequent Thermal Annealing

AbstractNonstoichiometric defects in carbides of the Group IV and V transition metals and radiation-induced atomic defects in SiC were studied by positron lifetime measurements before and after low-temperature (80 K) electron irradiation and subsequent thermal annealing up to 1900 K. Agglomeration of radiation-induced atomic defects which strongly depends on the energy of the irradiation electrons and subsequent decay of the agglomerates in SiC is observed.

Determination of Electron Distribution and Bonding from Soft X-Ray Emission Spectroscopy

1965 ◽  
Vol 9 ◽  
pp. 365-375 ◽  
Author(s):  
J. E. Holliday
Keyword(s):  
Transition Metal ◽  
Hexagonal Structure ◽  
Group Iv ◽  
Metal Carbides ◽  
Group Vi ◽  
Transition Metal Carbides ◽  
Chemical Combination ◽  
Long Tails ◽  
Metal Diborides

AbstractFrom measurements of the shift in wavelength with chemical combination, it appears there is very little transfer of charge between the metal and nonmetal atoms for the Group-IV transition-metal carbides and diborides. For Group-VI transition-metal carbides and beyond, there appears to be a definite transfer of charge from the carbon to the metal atom. The bonding in the Group-IV transitionmetal carbides is largely co valent, and metallic for the Group-IV transition-metal diborides. A comparison of shapes of emission bands with crystal structure indicates that, in general, NaCl-type structures have symmetrical peaks with narrow bandwidths compared to hexagonal structure, which have asymmetrical peaks, broad bandwidths, and long tails to the bottom of the bands.

Facile, low-temperature synthesis of tungsten carbide (WC) flakes for the sensitive and selective electrocatalytic detection of dopamine in biological samples

2019 ◽  
Vol 6 (8) ◽  
pp. 2024-2034 ◽  
Author(s):  
Muthaiah Annalakshmi ◽  
Paramasivam Balasubramanian ◽  
Shen-Ming Chen ◽  
Tse-Wei Chen ◽  
Pei-Hung Lin
Keyword(s):  
Low Temperature ◽  
Transition Metal ◽  
Tungsten Carbide ◽  
Biological Samples ◽  
Electronic Conductivity ◽  
Metal Carbides ◽  
Low Temperature Synthesis ◽  
Temperature Synthesis ◽  
Transition Metal Carbides ◽  
Electrochemical Applications

Transition metal carbides have shown potential for use in electrochemical applications due to their excellent electronic conductivity, stability and electrocatalysis.

Defects in Electron Irradiation Te-Doped GaSb Studied by Positron Lifetime Spectroscopy

2008 ◽  
Vol 607 ◽  
pp. 140-142
Author(s):  
H. Li ◽  
J.Y. Ke ◽  
J.B. Pang ◽  
Bo Wang ◽  
Z. Wang
Keyword(s):  
Electron Irradiation ◽  
Irradiation Dose ◽  
Room Temperature ◽  
Positron Lifetime ◽  
Rydberg States ◽  
Average Lifetime ◽  
Shallow Trap ◽  
Lifetime Measurements ◽  
Positron Lifetime Spectroscopy ◽  
Antisite Defects

Defects induced by electron irradiation in Te-doped liquid-encapsulated Czochralski–grown GaSb were studied by the positron lifetime spectroscopy. The lifetime measurements under room temperature indicated there were VGa-related defects with a characteristic lifetime of 298 ps in the heavily Te-doped as-grown GaSb samples. The average lifetime increased with the increase of irradiation dose in lightly Te-doped GaSb,but the behavior was opposite in the heavily Te-doped samples. It should be due to the shift of Fermi level in heavily Te-doped GaSb and the occurrence of gallium vacancies in different charge states. In the temperature dependence measurements carried out on heavily Te-doped samples, we observed positron shallow trap, and this shallow trap should be attributed to positrons forming hyrogenlike Rydberg states with GaSb antisite defects.

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