Regrowth of Ge with different degrees of damage under thermal and athermal treatment

RSC Advances ◽  
2016 ◽  
Vol 6 (6) ◽  
pp. 4576-4586 ◽  
Author(s):  
Sonu Hooda ◽  
B. Satpati ◽  
Tanuj Kumar ◽  
Sunil Ojha ◽  
D. Kanjilal ◽  
...  

In this report, the recrystallization of pre-damaged Ge samples is extensively investigated under steady-state thermal annealing and ultrafast thermal spike-assisted annealing generated by high-energy ions.

2021 ◽  
Author(s):  
Sutapa Dey ◽  
Anusmita Chakravorty ◽  
Shashi Bhusan Mishra ◽  
Nasima Khatun ◽  
Arnab Hazra ◽  
...  

Irradiation of materials by high energy ions (~MeV) causes intense electronic excitations through inelastic transfer of energy that significantly modifies physicochemical properties. We report the effect of 100 MeV Ag...


Author(s):  
Joseph J. Comer ◽  
Charles Bergeron ◽  
Lester F. Lowe

Using a Van De Graaff Accelerator thinned specimens were subjected to bombardment by 3 MeV N+ ions to fluences ranging from 4x1013 to 2x1016 ions/cm2. They were then examined by transmission electron microscopy and reflection electron diffraction using a 100 KV electron beam.At the lowest fluence of 4x1013 ions/cm2 diffraction patterns of the specimens contained Kikuchi lines which appeared somewhat broader and more diffuse than those obtained on unirradiated material. No damage could be detected by transmission electron microscopy in unannealed specimens. However, Dauphiné twinning was particularly pronounced after heating to 665°C for one hour and cooling to room temperature. The twins, seen in Fig. 1, were often less than .25 μm in size, smaller than those formed in unirradiated material and present in greater number. The results are in agreement with earlier observations on the effect of electron beam damage on Dauphiné twinning.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
H. Amekura ◽  
M. Toulemonde ◽  
K. Narumi ◽  
R. Li ◽  
A. Chiba ◽  
...  

AbstractDamaged regions of cylindrical shapes called ion tracks, typically in nano-meters wide and tens micro-meters long, are formed along the ion trajectories in many insulators, when high energy ions in the electronic stopping regime are injected. In most cases, the ion tracks were assumed as consequences of dense electronic energy deposition from the high energy ions, except some cases where the synergy effect with the nuclear energy deposition plays an important role. In crystalline Si (c-Si), no tracks have been observed with any monomer ions up to GeV. Tracks are formed in c-Si under 40 MeV fullerene (C60) cluster ion irradiation, which provides much higher energy deposition than monomer ions. The track diameter decreases with decreasing the ion energy until they disappear at an extrapolated value of ~ 17 MeV. However, here we report the track formation of 10 nm in diameter under C60 ion irradiation of 6 MeV, i.e., much lower than the extrapolated threshold. The diameters of 10 nm were comparable to those under 40 MeV C60 irradiation. Furthermore, the tracks formed by 6 MeV C60 irradiation consisted of damaged crystalline, while those formed by 40 MeV C60 irradiation were amorphous. The track formation was observed down to 1 MeV and probably lower with decreasing the track diameters. The track lengths were much shorter than those expected from the drop of Se below the threshold. These track formations at such low energies cannot be explained by the conventional purely electronic energy deposition mechanism, indicating another origin, e.g., the synergy effect between the electronic and nuclear energy depositions, or dual transitions of transient melting and boiling.


1990 ◽  
Vol 258 (5) ◽  
pp. H1357-H1365 ◽  
Author(s):  
E. D. Lewandowski ◽  
D. L. Johnston

13C and 31P nuclear magnetic resonance (NMR) spectra were used to assess substrate oxidation and high-energy phosphates in postischemic (PI) isolated rabbit hearts. Phosphocreatine (PCr) increased in nonischemic controls on switching from glucose perfusion to either 2.5 mM [3-13C]pyruvate (120%, n = 7) or [2-13C]acetate (114%, n = 8, P less than 0.05). ATP content, oxygen consumption (MVO2), and hemodynamics (dP/dt) were not affected by substrate availability in control or PI hearts. dP/dt was 40-60% lower in PI hearts during reperfusion after 10 min ischemia. Hearts reperfused with either pyruvate (n = 11) or acetate (n = 8) regained preischemic PCr levels within 45 s. Steady-state ATP levels were 55-70% of preischemia with pyruvate and 52-60% with acetate. Percent maximum [4-13C]glutamate signal showed reduced conversion of pyruvate to glutamate via the tricarboxylic acid (TCA) cycle at 4-min reperfusion (PI = 24 +/- 4%, means +/- SE; Control = 48 +/- 4%). The increase in 13C signal from the C-4 position of glutamate was similar to control hearts within 10.5 min. The increase in [4-13C]glutamate signal from acetate was not different between PI and control hearts. The ratio of [2-13C]Glu:[4-13C]Glu, reflecting TCA cycle activity, was reduced in PI hearts with acetate for at least 10 min (Control = 0.76 +/- 0.03; PI = 0.51 +/- 0.09) until steady state was reached. Despite rapid recovery of oxidative phosphorylation, contractility remained impaired and substrate oxidation was significantly slowed in postischemic hearts.


2013 ◽  
Vol 50 ◽  
pp. 92-96 ◽  
Author(s):  
Y. Fukuda ◽  
H. Sakaki ◽  
M. Kanasaki ◽  
A. Yogo ◽  
S. Jinno ◽  
...  

2013 ◽  
Vol 781-784 ◽  
pp. 357-361 ◽  
Author(s):  
Igor V. Khromushin ◽  
Taтiana I. Aksenova ◽  
Turgora Tuseyev ◽  
Karlygash K. Munasbaeva ◽  
Yuri V. Ermolaev ◽  
...  

The effect of irradiation with heavy ions Ne, Ar, and Kr of various energies on the structure and properties of ceramic barium cerate doped with neodymium and annealed in air at 650°C for 7 hours is studied. It is noted that blistering was observed on cerate surface during its irradiation by low energy Ne ions, whereas it was not observed under low-energy Ar and Kr ions irradiation. Irradiation of the cerate with high energy ions caused partial amorphization of the irradiated surface of the material, while the structure of the non-irradiated surface did not change. In addition, the irradiated surface of the cerate endured solid-phase structural changes. Thus, upon high-energy ions irradiation in the range of Ne, Ar, Kr the cerate surface resembled the stages of spherulite formation - nucleation, growth (view of cauliflower), formation of spherulitic crust, respectively. The increase in water molecules release and reduction of molecular oxygen release from the barium cerate, irradiated by high-energy ions is found during vacuum constant rate heating. It is concluded that cerates undergo changes to the distances significantly exceeding the ion ranges in these materials. Features of high-energy ions influence on thermal desorption of carbon dioxide from cerates show, apparently, the formation of weakly bound carbonate compounds on the cerate surface in the irradiation process.


RSC Advances ◽  
2014 ◽  
Vol 4 (73) ◽  
pp. 38718-38725 ◽  
Author(s):  
Fengyuan Lu ◽  
Tiankai Yao ◽  
Jinling Xu ◽  
Jingxian Wang ◽  
Spencer Scott ◽  
...  

High energy ball milled iodoapatite in the form of an amorphous matrix embedded with nanocrystals can be readily crystallized by subsequent low temperature thermal annealing, which greatly improves the thermal stability and iodine confinement.


The results in this paper are based on an entirely different choice of the undetermined coupling constant f which appears in the theory of creation of matter. Previously f was chosen to make the steady-state expansion rate coincident with the observed expansion rate. Now that we take a much larger value for f , the corresponding steady-state expansion rate is much greater than the observed value. We interpret this difference as showing that we live in a wide, possibly temporary, fluctuation from the steady-state situation. The expansion rate in such a fluctuation follows the Einstein-de Sitter relations. The natural scale set by the new steady-state corresponds to the masses of clusters of galaxies, we obtain 10 13 M0 instead of 10 23 M@ for the ‘observable universe’. It is suggested that elliptical galaxies were formed early in the development of a fluctuation. Our discussion of high energy phenomena leads to im m ediate explanations of the energy spectrum of cosmic rays, of the presence of e + in cosmic rays and of the rate of energy production associated with radio sources.


2021 ◽  
Author(s):  
Yuto Nakayama ◽  
Hiromu Kawasaki ◽  
Takeshi Higashiguchi

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