scholarly journals THz-Enhanced DC Ultrafast Electron Diffractometer

2021 ◽  
Vol 2021 ◽  
pp. 1-7
Author(s):  
Dongfang Zhang ◽  
Tobias Kroh ◽  
Felix Ritzkowsky ◽  
Timm Rohwer ◽  
Moein Fakhari ◽  
...  
Keyword(s):  
Structural Dynamics ◽  
Pulse Compression ◽  
Electron Beams ◽  
Single Crystal Silicon ◽  
High Quality ◽  
Crystal Silicon ◽  
Electron Sources ◽  
Electron Bunches ◽  
Diffraction Patterns ◽  
Proof Of Principle

Terahertz- (THz-) based electron manipulation has recently been shown to hold tremendous promise as a technology for manipulating and driving the next generation of compact ultrafast electron sources. Here, we demonstrate an ultrafast electron diffractometer with THz-driven pulse compression. The electron bunches from a conventional DC gun are compressed by a factor of 10 and reach a duration of ~180 fs (FWHM) with 10,000 electrons/pulse at a 1 kHz repetition rate. The resulting ultrafast electron source is used in a proof-of-principle experiment to probe the photoinduced dynamics of single-crystal silicon. The THz-compressed electron beams produce high-quality diffraction patterns and enable the observation of the ultrafast structural dynamics with improved time resolution. These results validate the maturity of THz-driven ultrafast electron sources for use in precision applications.

Fabrication of High Quality Silicide Layers by Ion Implantation

1989 ◽  
Vol 147 ◽  
Author(s):  
Karen J Reeson ◽  
Ann De Veirman ◽  
Russell Gwilliam ◽  
Chris Jeynes ◽  
Brian J Sealy ◽  
...  
Keyword(s):  
Ion Implantation ◽  
Single Crystal Silicon ◽  
High Quality ◽  
Crystal Silicon ◽  
The Matrix ◽  
Buried Layer ◽  
Buried Layers ◽  
C 30 ◽  
Type Lattice ◽  
Anneal Temperature

AbstractBuried layers of CoSi2 have been successfully fabricated in (100) single crystal silicon by implanting 350 keV Co+ to doses in the range 2 - 7 × 1017 cm−2 at a temperature of ∼550°C. For doses ≥ 4 × 101759Co+ cm−2, a continuous buried layer of CoSi2 grows epitaxially, during implantation. After annealing (1000°C 30 minutes) continuous layers of stoichiometric CoSi2 which are coherent with the matrix are produced for doses ≥ 4 × 101759Co+ cm−2. For doses of ≤ 2 × 101759Co+, cm−2, discrete octahedral precipitates of monocrystalline CoSi2 are observed. Isochronal annealing (for 5s) at temperatures in the range 800–1200°C, shows that at temperatures ≥ 900°C there is significant redistribution of the Co from B-type or interstitial sites → substitutional A-type lattice sites. As the anneal temperature is increased there is a corresponding improvement in the crystallinity and coherency of the Si and CoSi2 lattices. This shows that at a given temperature much of the Co redistribution takes place within the first 5s of the anneal.

Silicon Carbide: Progress in Crystal Growth

1987 ◽  
Vol 97 ◽  
Author(s):  
J. Anthony Powell
Keyword(s):  
Silicon Carbide ◽  
Crystal Growth ◽  
High Temperature ◽  
Epitaxial Growth ◽  
Recent Progress ◽  
Single Crystal Silicon ◽  
Silicon Substrates ◽  
Large Area ◽  
High Quality ◽  
Crystal Silicon

ABSTRACTSilicon carbide (SiC), with a favorable combination of semiconducting and refractory properties, has long been a candidate for high temperature semiconductor applications. Research on processes for producing the needed large-area high quality single crystals has proceeded sporadically for many years. Two characteristics of SiC have aggravated the problem of its crystal growth. First, it cannot be melted at any reasonable pressure, and second, it forms many different crystalline structures, called polytypes. Recent progress in the development of two crystal growth processes will be described. These processes are the modified Lely process for the growth of the alpha polytypes (e.g. 6H SiC), and a process for the epitaxial growth of the beta polytype (i.e. 3C or cubic SiC) on single crystal silicon substrates. A discussion of the semiconducting qualities of crystals grown by various techniques will also be included.

Flat-plate single-crystal silicon sample holders for neutron powder diffraction studies of highly absorbing gadolinium compounds

2008 ◽  
Vol 41 (1) ◽  
pp. 198-205 ◽  
Author(s):  
D. H. Ryan ◽  
L. M. D. Cranswick
Keyword(s):  
Single Crystal ◽  
Flat Plate ◽  
Single Crystal Silicon ◽  
Magnetic Ordering ◽  
Silicon Sample ◽  
Large Area ◽  
Crystal Silicon ◽  
Thin Sample ◽  
Diffraction Patterns ◽  
Alloys And Compounds

The extreme absorption cross section of natural gadolinium has so far precluded routine neutron diffraction work on its alloys and compounds. However, it is shown here that an easily constructed flat-plate sample holder with silicon single-crystal windows can be used to place a thin layer of material in a neutron beam and obtain Rietveld refinement quality diffraction data in a modest time. The flat-plate geometry uses a large area to compensate for the necessarily thin sample. Demonstration data are presented on two intermetallic compounds, Sm3Ag4Sn4and Gd3Ag4Sn4, and it is shown that both structural and magnetic information can be derived from the diffraction patterns. By working at a wavelength of 2.37 Å, it is possible to observe the low-Qdiffraction peaks associated with magnetic ordering. This simple methodology should now enable routine measurements on even the most highly absorbing materials.

Development of a Combined Diamond Impregnated Lapping Plate

2017 ◽  
Vol 739 ◽  
pp. 157-163
Author(s):  
Guan Fu Lin ◽  
Ming Yi Tsai ◽  
Chiu Yuan Chen
Keyword(s):  
Surface Roughness ◽  
Material Removal Rate ◽  
Material Removal ◽  
Removal Rate ◽  
Single Crystal Silicon ◽  
High Quality ◽  
Crystal Silicon ◽  
Temperature Heating ◽  
Oxidized Diamond ◽  
High Temperature Heating

This paper presents a combined diamond-impregnated lapping plate for single crystal silicon carbide (SiC) to improve the material removal rate due to SiC having very low material removal rate. Three different dimaond shapes were prepared: (1) "sharp," a sharp-edged diamod; (2) "blocky," a high quality crystalline diamond; (3) "oxidized diamond". The diamonds were manufactured by using high temperature heating method in a furnace to induce diamond oxidation resulting in improvement of Ra and sharpness of the diamonds. Three combined diamond-impregnated lapping plates were fabricated using the above mentioned diamond shapes with diamond size of 6μm. The surface roughness and removal rate of the SiC lapping with these plate were investigated. Experimental results showed that the average material removal rate (MRR) of oxidized diamond is higher than that of the other diamond shapes. The MRR of oxidized diamond for C-face and Si-face SiC are 4.72μm/hr and 6.26μm/hr, respectively. It is found that the surface roughness (Ra) of oxidized diamond for C-face and Si-face are 7.547nm and 8.06nm, respectively. This indicates that the combined diamond-impregnated lapping plate can be effectively used for SiC machining.

High quality single shot diffraction patterns using ultrashort megaelectron volt electron beams from a radio frequency photoinjector

2010 ◽  
Vol 81 (1) ◽  
pp. 013306 ◽  
Author(s):  
P. Musumeci ◽  
J. T. Moody ◽  
C. M. Scoby ◽  
M. S. Gutierrez ◽  
H. A. Bender ◽  
...  
Keyword(s):  
Radio Frequency ◽  
Electron Beams ◽  
Single Shot ◽  
High Quality ◽  
Diffraction Patterns

Dynamic investigation of defects induced by short, high current pulses of high energy lithium ions

2014 ◽  
Vol 1712 ◽  
Author(s):  
Hua Guo ◽  
Arun Persaud ◽  
Steve Lidia ◽  
Andrew M. Minor ◽  
P. Hosemann ◽  
...  
Keyword(s):  
Pulse Compression ◽  
Ion Beam ◽  
National Laboratory ◽  
Single Crystal Silicon ◽  
High Energy ◽  
Probe Type ◽  
Relaxation Dynamics ◽  
Crystal Silicon ◽  
Transmitted Beam ◽  
Induction Type

ABSTRACTWe employ intense and short pulses of energetic lithium (Li+) ions to investigate the relaxation dynamics of radiation induced defects in single crystal silicon samples. Ions both create damage and track damage evolution simultaneously at short time scales when we use the channeling effect as a diagnostic tool. Ion pulses, ∼20 to 600 ns long and with peak currents of up to ∼1 A are formed in an induction type linear accelerator, the Neutralized Drift Compression eXperiment at Lawrence Berkeley National Laboratory. By rotating silicon (<100>) membranes of different thicknesses and changing the incident ion energy, the fraction of channeled ions in the transmitted beam could be varied. In preliminary experiments we find that the Li ion intensity is not high enough to generate overlapping cascades (in time and space) that would be necessary to measure a change in the shape of the current waveform of the transmitted ion beam. We discuss the concept of pump-probe type experiments with short ion beam pulses to access defect dynamics in materials and outline a path to increasing damage rates with heavier ions and by the application of longitudinal and lateral pulse compression techniques.

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