Oxidation Induced ON1, ON2a/b Defects in 4H-SiC Characterized by DLTS

2014 ◽  
Vol 778-780 ◽  
pp. 281-284 ◽  
Author(s):  
Ian D. Booker ◽  
Hassan Abdalla ◽  
Louise Lilja ◽  
Jawad ul Hassan ◽  
Peder Bergman ◽  
...  

The deep levels ON1and ON2a/bintroduced by oxidation into 4H-SiC are characterized via standard DLTS and via filling pulse dependent DLTS measurements. Separation of the closely spaced ON2a/bdefect is achieved by using a higher resolution correlation function (Gaver-Stehfest 4) and apparent energy level, apparent electron capture cross section and filling pulse measurement derived capture cross sections are given.

1953 ◽  
Vol 31 (3) ◽  
pp. 204-206 ◽  
Author(s):  
Rosalie M. Bartholomew ◽  
R. C. Hawkings ◽  
W. F. Merritt ◽  
L. Yaffe

The thermal neutron capture cross sections of Na23 and Mn55 have been determined using the activation method. The values are 0.53 ± 0.03 and 12.7 ± 0.3 barns respectively with respect to σAul97 = 93 barns. These agree well with recent pile oscillator results. The half-life for Mn56 is found to be 2.576 ± 0.002 hr.


1954 ◽  
Vol 32 (4) ◽  
pp. 275-290 ◽  
Author(s):  
A. Charles Whittier

A proton beam was directed through hydrogen gas at low pressure and magnetic analysis of the emergent beam showed that an appreciable fraction of the beam was transformed into negative hydrogen ions. After the beam had traversed a sufficient layer of gas, the ratio of negative hydrogen ions to protons reached an equilibrium value which was a maximum of 22.2% at 8.5 kev. The proton energy interval investigated extended from 4 to 70 kev.In this interval the electron loss cross section for negative hydrogen ions was measured and found to vary from 6.3 × 10−16 sq. cm. at 4.2 kev. to 2.5 × 10−10 sq. cm. at 70.3 kev. The electron capture cross section for protons in hydrogen was measured over the same interval and the results agreed substantially with those of other workers. The electron capture cross section for neutral atoms was also determined by combining present results for the negative ion loss cross section and for the equilibrium ratio of H− to H+ with the values of Bartels and of Montague and Ribe for the ratio of neutral atom loss cross section to the proton capture cross section.


1941 ◽  
Vol 19a (3) ◽  
pp. 33-41 ◽  
Author(s):  
E. L. Harrington ◽  
J. L. Stewart

A comparison method of measuring, by using solutions, the capture cross-sections for thermal neutrons is described. The chief advantages are directness, simplicity, and freedom from uncertainties as to direction of path, or as to the magnitude of the scattering effect. The method is best suited to nuclei of large cross-sections. Assuming the well checked value for the cadmium nucleus to be correct, the capture cross-sections of certain other nuclei were determined. The results for barium and for hydrogen differ widely from values previously published.


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