Investigation of surface defects on Ni(110) with a low-energy positron beam

1987 ◽  
Vol 35 (3) ◽  
pp. 1034-1038 ◽  
Author(s):  
A. R. Köymen ◽  
D. W. Gidley ◽  
T. W. Capehart
Keyword(s):  
Surface Defects ◽  
Positron Beam ◽  
Low Energy

scholarly journals Colloidal CdSe nanocrystals are inherently defective

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Tamar Goldzak ◽  
Alexandra R. McIsaac ◽  
Troy Van Voorhis
Keyword(s):  
Charge Transfer ◽  
Energy Spectrum ◽  
Surface Structure ◽  
Short Range ◽  
Surface Defects ◽  
Low Energy ◽  
Lewis Base ◽  
Cdse Nanocrystals ◽  
Photoinduced Charge Transfer ◽  
Photoinduced Charge

AbstractColloidal CdSe nanocrystals (NCs) have shown promise in applications ranging from LED displays to medical imaging. Their unique photophysics depend sensitively on the presence or absence of surface defects. Using simulations, we show that CdSe NCs are inherently defective; even for stoichiometric NCs with perfect ligand passivation and no vacancies or defects, we still observe that the low energy spectrum is dominated by dark, surface-associated excitations, which are more numerous in larger NCs. Surface structure analysis shows that the majority of these states involve holes that are localized on two-coordinate Se atoms. As chalcogenide atoms are not passivated by any Lewis base ligand, varying the ligand should not dramatically change the number of dark states, which we confirm by simulating three passivation schemes. Our results have significant implications for understanding CdSe NC photophysics, and suggest that photochemistry and short-range photoinduced charge transfer should be much more facile than previously anticipated.

Low energy positron beam studies of nano-TiN films

1994 ◽  
Vol 26 (2-3) ◽  
pp. 163-166 ◽  
Author(s):  
Huimin Weng ◽  
Dazhi Wang ◽  
Rongdian Han ◽  
Yi Jiang ◽  
Genqing Yang ◽  
...  
Keyword(s):  
Positron Beam ◽  
Low Energy ◽  
Tin Films

Defect Formation by Ion Implantation in Cz-Si Studied by a Monoenergetic Positron Beam

1992 ◽  
Vol 262 ◽  
Author(s):  
A. Uedono ◽  
Y. Ujihira ◽  
L. Wei ◽  
Y. Tabuki ◽  
S. Tanigawa ◽  
...  
Keyword(s):  
Oxygen Vacancy ◽  
Ion Implantation ◽  
Defect Formation ◽  
Positron Beam ◽  
Low Energy ◽  
Doppler Broadening ◽  
Positron Energy ◽  
Annealing Experiments ◽  
Incident Positron ◽  
Ion Implanted

ABSTRACTVacancy-type defects in ion implanted Si were studied by a monoenergetic positron beam. The depth-distributions of the defects were obtained from measurements of Doppler broadening profiles of the positron annihilation as a function of incident positron energy. The results showed that a size of vacany-clusters introduced by 150-keV P+-ion implantation was found to be smaller than that introduced by 2-MeV P+-ion implantation. This was attributed to an overlap of collision cascades in low-energy (150 keV) ion implanted specimens. From isochronal annealing experiments for 80-keV B+- and 150-keV P+-ion implanted specimens, the defected region was removed by 1200 °C annealing, however, for 2-MeV P+-implanted specimen, two-types of oxygen-vacancy complexes were found to coexist even after 1200 °C annealing.

Near-surface defects in hydrogen-plasma-treated boron-doped silicon studied by positron beam spectroscopy

1999 ◽  
Vol 68 (6) ◽  
pp. 643-645 ◽  
Author(s):  
C.E. Gonzalez ◽  
S.C. Sharma ◽  
N. Hozhabri ◽  
D.Z. Chi ◽  
S. Ashok
Keyword(s):  
Surface Defects ◽  
Hydrogen Plasma ◽  
Positron Beam ◽  
Near Surface ◽  
Boron Doped ◽  
Doped Silicon

scholarly journals Modelling the line shape of very low energy peaks of positron beam induced secondary electrons measured using a time of flight spectrometer

2017 ◽  
Vol 791 ◽  
pp. 012030 ◽  
Author(s):  
A J Fairchild ◽  
V A Chirayath ◽  
R W Gladen ◽  
M D Chrysler ◽  
A R Koymen ◽  
...  
Keyword(s):  
Line Shape ◽  
Time Of Flight ◽  
Positron Beam ◽  
Low Energy ◽  
Secondary Electrons

Low Energy Electron Microscopy of Surface Processes on Clean Si(111) and Si (100)

1989 ◽  
Vol 159 ◽  
Author(s):  
E. Bauer ◽  
M. Mundschau ◽  
W. Swiech ◽  
W. Telieps
Keyword(s):  
Electron Microscopy ◽  
Phase Transitions ◽  
Crystal Growth ◽  
Surface Defects ◽  
Low Energy ◽  
Energy Electron ◽  
Surface Processes ◽  
Surface Phase ◽  
Surface Phase Transitions ◽  
Low Energy Electron

ABSTRACTLow energy electron microscopy (LEEM) is briefly introduced and its application to the study of surface defects, surface phase transitions on Si(111), crystal growth and sublimation on Si(100) is illustrated.

Effect of surface defects on charge exchange of low-energy deuterium ions scattered fromSrCl2andBaF2

1998 ◽  
Vol 58 (7) ◽  
pp. 4143-4148 ◽  
Author(s):  
R. Souda ◽  
T. Suzuki ◽  
H. Kawanowa ◽  
E. Asari
Keyword(s):  
Charge Exchange ◽  
Surface Defects ◽  
Low Energy ◽  
Effect Of Surface

Growth of semiconductor layers studied by spot profile analysing low energy electron diffraction – Part I1

1999 ◽  
Vol 214 (10) ◽  
Author(s):  
M. Horn-von Hoegen
Keyword(s):  
Electron Diffraction ◽  
Surface Defects ◽  
Profile Analysis ◽  
Domain Size ◽  
Low Energy ◽  
Energy Electron ◽  
Vicinal Surfaces ◽  
Low Energy Electron Diffraction ◽  
Facet Orientation ◽  
Low Energy Electron

AbstractThe universal capabilities of high resolution spot profile analysis low energy electron diffraction for in situ studies of surface morphology and surface defects will be discussed and demonstrated. The position of the diffraction spots is used to determine lateral lattice constants, step heights and the strain state of heterosystems with a precision of 0.02 Å. With the knowledge of the spot profile we could determine island and domain size distributions – even during deposition – and correlation functions of arbitrary surface defects. The variation of the spot profile with electron energy allows the evaluation of the 3dim. reciprocal space. With this the power spectrum of surface roughness, facet orientation, or step morphology of flat and vicinal surfaces could be completely characterised.

Production of a monochromatic, low energy positron beam using the 11B(p,n)11C reaction

1974 ◽  
Vol 45 (7) ◽  
pp. 951-953 ◽  
Author(s):  
T. S. Stein ◽  
W. E. Kauppila ◽  
L. O. Roellig
Keyword(s):  
Positron Beam ◽  
Low Energy
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