scholarly journals Doppler-broadening of annihilation radiation spectroscopy under high magnetic field using a longitudinally spin-polarized slow positron beam

2014 ◽  
Author(s):  
Masaki Maekawa ◽  
Hongjun Zhang ◽  
Hui Li ◽  
Yuki Fukaya ◽  
Atsuo Kawasuso
Keyword(s):  
Magnetic Field ◽  
High Magnetic Field ◽  
Positron Beam ◽  
Annihilation Radiation ◽  
Doppler Broadening ◽  
Slow Positron ◽  
Spin Polarized

scholarly journals Study of Microvoids in High-Rate a-Si:H Using Positron Annihilation

1997 ◽  
Vol 467 ◽  
Author(s):  
X. Zou ◽  
D. P. Webb ◽  
S. H. Lin ◽  
Y. W. Lam ◽  
Y. C. Chan ◽  
...  
Keyword(s):  
Thin Films ◽  
Positron Annihilation ◽  
Surface Region ◽  
Positron Beam ◽  
High Rate ◽  
Doppler Broadening ◽  
Slow Positron ◽  
Depth Profiles ◽  
Vacancy Type Defect ◽  
Low Rate

ABSTRACTIn this paper, we have carried out the positron annihilation measurement on high-rate and low-rate a-Si:H thin films deposited by PECVD. By means of the slow positron beam Doppler-broadening technique, the depth profiles of microvoids in a-Si:H have been determined. We have also studied the vacancy-type defect in the surface region in high-rate grown a-Si:H, making comparison between high-rate and low-rate a-Si:H. By plotting S and W parameters in the (S, W) plane, we have shown that the vacancies in all of the high-rate and low-rate deposited intrinsic samples, and in differently doped low-rate samples are of the same nature.

The design of a spin-polarized slow positron beam

2000 ◽  
Vol 58 (5-6) ◽  
pp. 759-762 ◽  
Author(s):  
J.H Kim ◽  
F Saito ◽  
Y Nagashima ◽  
T Kurihara ◽  
A Goto ◽  
...  
Keyword(s):  
Positron Beam ◽  
Slow Positron ◽  
Spin Polarized

Effect of Sintering on Defects in Yttria Stabilised Zirconia

2012 ◽  
Vol 733 ◽  
pp. 236-239 ◽  
Author(s):  
Ivan Procházka ◽  
Jakub Čížek ◽  
Oksana Melikhova ◽  
Wolfgang Anwand ◽  
Gerhard Brauer ◽  
...  
Keyword(s):  
Elevated Temperatures ◽  
Subsurface Layer ◽  
Positron Beam ◽  
Annihilation Radiation ◽  
Strong Suppression ◽  
Slow Positron ◽  
Open Volume ◽  
Zirconia Nanopowders ◽  
Variable Energy

A variable energy slow positron beam was utilised to investigate depth dependent effects of sintering on the tetragonal yttria stabilised zirconia nanopowders. Positron implantation was combined with the determination of Doppler broadened profiles of annihilation radiation. The results are consistent with recent positron lifetime data showing that sintering at elevated temperatures leads to a disappearance of pores and a significant grain growth, which is demonstrated by a strong suppression of positronium formation and a substantial decrease in concentration of open volume defects at triple points, respectively, with increasing sintering temperature. An existence of a subsurface layer of a relatively high content of defects was shown in sintered samples and tentatively attributed to arise from a diffusion of open volume defects from the sample interior toward the surface or from a sintering-induced surface modification.

The Behavior of Oxygen and Defects in Si-Based Semiconductor Studied by Positron Annihilation Techniques

2008 ◽  
Vol 607 ◽  
pp. 131-133
Author(s):  
Wen Deng ◽  
Le Huang ◽  
Qi Tao Zhu ◽  
Ya Qin Wei ◽  
Yu Yang Huang
Keyword(s):  
Heat Treatment ◽  
Structural Changes ◽  
Positron Beam ◽  
Sio2 Film ◽  
Doppler Broadening ◽  
Slow Positron ◽  
Initial Oxygen Content ◽  
Initial Oxygen ◽  
One Step ◽  
Induced Defects

Slow positron beam and coincidence Doppler broadening techniques have been used to follow temperature-induced defects and structural changes in Cz-Si with an initial oxygen content of 1.1×1018 cm-3. Oxygen is recognized as a peak at about 11.85×10-3m0c on the ratio curves. For Cz-Si annealed at 480 oC/15h or 600 oC/15h, the ratio curves show the presence of vacancy-like defects, but they are not associated with oxygen. For Cz-Si annealed at 480 oC/15h, then followed by a 600 oC/15h heat treatment, the ratio curves show the signal of O atom. The ratio curves of Cz-Si, thermally treated by a two-step (480oC/15h + 600oC/15h) pre-annealing, followed by a one-step annealing under different hydrostatic argon pressures and annealed temperatures, also show a peak at 11.85×10-3m0c. The height of the peak varies with different samples. Experimental results indicate that the SiO2 film will form on the surface of Cz-Si after the heat treatment.

Slow Positron Beam with Small Energy Spread in the Magnetic Field Using Reflection Type Remoderator

1997 ◽  
Vol 255-257 ◽  
pp. 677-679 ◽  
Author(s):  
Yoshihide Honda ◽  
Masaki Maekawa ◽  
N. Kimura ◽  
T. Kozawa ◽  
S. Nishijima ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Positron Beam ◽  
Energy Spread ◽  
Small Energy ◽  
Slow Positron ◽  
The Magnetic Field

Positron Doppler broadening measurements with a LINAC-based slow positron beam

1995 ◽  
Vol 85 ◽  
pp. 172-177
Author(s):  
D. Segers ◽  
J. Paridaens ◽  
T. Van Hoecke ◽  
C. Dauwe ◽  
L. Dorikens-Vanpraet ◽  
...  
Keyword(s):  
Positron Beam ◽  
Doppler Broadening ◽  
Slow Positron

HOT PHOTOLUMINESCENCE STUDY OF MINIBAND EFFECTS IN GaAs/AlAsSLs

2003 ◽  
Vol 02 (06) ◽  
pp. 383-389
Author(s):  
D. N. MIRLIN ◽  
V. F. SAPEGA ◽  
V. M. USTINOV
Keyword(s):  
Magnetic Field ◽  
High Magnetic Field ◽  
Growth Direction ◽  
Vertical Transport ◽  
Hot Electrons ◽  
Hot Electron ◽  
Photoluminescence Study ◽  
Spin Polarized

We report the study of the effect of miniband width on polarization properties of the hot electron photoluminescence (HPL) in SLs . It is demonstrated that the energy and magnetic field dependencies of the HPL polarization are very sensitive to the electron miniband widths. We show that high magnetic field applied perpendicular to the SL growth direction (Voigt geometry) induces transition (magnetic field breakdown) between electron minibands. The vertical transport of spin polarized and momentum aligned hot electrons is studied.

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