scholarly journals Microstructure Evolution in He-Implanted Si at 600 °C Followed by 1000 °C Annealing

Materials ◽  
2021 ◽  
Vol 14 (17) ◽  
pp. 5107
Author(s):  
Zhen Yang ◽  
Zhiping Zou ◽  
Zeyang Zhang ◽  
Yubo Xing ◽  
Tao Wang

Si single crystal was implanted with 230 keV He+ ions to a fluence of 5 × 1016/cm2 at 600 °C. The structural defects in Si implanted with He at 600 °C and then annealed at 1000 °C were investigated by transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM). The microstructure of an as-implanted sample is provided for comparison. After annealing, rod-like defects were diminished, while tangled dislocations and large dislocation loops appeared. Dislocation lines trapped by cavities were directly observed. The cavities remained stable except for a transition of shape, from octahedron to tetrakaidecahedron. Stacking-fault tetrahedrons were found simultaneously. Cavity growth was independent of dislocations. The evolution of observed lattice defects is discussed.

2015 ◽  
Vol 1760 ◽  
Author(s):  
Norihiko L. Okamoto ◽  
Akira Yasuhara ◽  
Katsushi Tanaka ◽  
Haruyuki Inui

ABSTRACTThe crystal structure of the δ1p phase in the Fe-Zn system has been refined by single-crystal synchrotron X-ray diffraction combined with ultra-high resolution scanning transmission electron microscopy. The crystal structure can be described to build up with Fe-centered Zn12 icosahedra. The deformation properties obtained by single-crystal micropillar compression tests of the δ1p phase is discussed in terms of the arrangement of the Fe-centered Zn12 icosahedra in contrast with the ζ phase in the Fe-Zn system.


1998 ◽  
Vol 553 ◽  
Author(s):  
C. Reich ◽  
M. Conrad ◽  
F. Krumeich ◽  
B. Harbrecht

AbstractThe dodecagonal (dd) quasicrystalline tantalum telluride dd Ta1.6Te and the crystalline approximant Ta97Te60 have been modified by partly replacing tantalum by vanadium. The impact of the substitution on the structures has been studied by X-ray and electron diffraction and by high-resolution transmission electron microscopy. The layered-type approximant structure of Ta83V14Te60 was determined by single crystal X-ray means. The partitioning of vanadium on 21 out of 29 crystallographically inequivalent metal sites is referred to, but not controlled by the Dirichlet domain volume available at the sites. A HRTEM projection of dd (Ta, V)1.6Te onto the dodecagonal plane is analysed with respect to the arrangement of (Ta, V)151Te74 clusters on the vertices of an irregular aperiodic square-triangle tiling, the edge length of which corresponds to the distance between the centres of two such clusters. The clusters comprise about 1 nm thick corrugated lamellae which are periodically stacked by weak Te-Te interactions.


1986 ◽  
Vol 82 ◽  
Author(s):  
P. Ehrhart ◽  
W. Jäger ◽  
W. Schilling ◽  
F. Dworschak ◽  
Afaf A. Gadalla ◽  
...  

ABSTRACTThe evolution of the defect structure in 3 MeV-proton irradiated Cu and Ni has been investigated by transmission electron microscopy and by differential dilatometry. The proton irradiations were performed at T≦100°C up to irradiation doses of 2 dpa. An efficient loss of selfinterstitial atoms at dislocations and a consequently high average concentration of vacancies in clusters is observed starting from rather low fluences. In addition an ordering of the defects in the form of periodic {001} walls with a typical periodicity length of ≈ 60 nm is observed for all equivalent {001} planes. The walls consist of high local concentrations of dislocations, dislocation loops and stacking-fault tetrahedra. The observed formation of periodic arraysof defect walls is considered as an example for a possibly general microstructural phenomenon in metals under irradiation.


2018 ◽  
Vol 90 (5) ◽  
pp. 833-844
Author(s):  
Leonid Aslanov ◽  
Valery Zakharov ◽  
Ksenia Paseshnichenko ◽  
Aleksandr Yatsenko ◽  
Andrey Orekhov ◽  
...  

AbstractA new method for synthesis of 2D nanocrystals in water was proposed. The use of perfluorothiophenolate ions as surfactant allowed us to produce 2D single-crystal nanosheets of CaS at pH=9 and flat nanocrystals of PbS at pH=9 at room temperature. Mesocrystalline nanobelts of CdS and mesocrystals of PbS were obtained at pH=3–5 and pH=10–12, respectively. Morphology, structure and chemical composition of nanoparticles were characterized by high-resolution transmission electron microscopy, electron diffraction and energy dispersive X-ray spectroscopy. A mechanism of nanoparticles formation was discussed.


2002 ◽  
Vol 17 (1) ◽  
pp. 204-213 ◽  
Author(s):  
G. Y. Yang ◽  
J. M. Finder ◽  
J. Wang ◽  
Z. L. Wang ◽  
Z. Yu ◽  
...  

Microstructure in the SrTiO3/Si system has been studied using high-resolution transmission electron microscopy and image simulations. SrTiO3 grows heteroepitaxially on Si with the orientation relationship given by (001)STO//(001)Si and [100]STO//[110]Si. The lattice misfit between the SrTiO3 thin films and the Si substrate is accommodated by the presence of interfacial dislocations at the Si substrate side. The interface most likely consists of Si bonded to O in SrTiO3. The alternative presentation of Sr and Si atoms along the interface leads to the formation of 2× and 3× Sr configurations. Structural defects in the SrTiO3 thin film mainly consist of tilted domains and dislocations.


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