Practical realization of stable and high brightness sources of ultra-short electron pulses is an important issue in the development of time-resolved electron microscopy for the study of ultra-fast dynamics in materials. Here, we report on the experimental investigation of static (in the dark) and pulsed (under illumination by sub-picosecond laser pulses at 1040 nm) electron emission from single-crystal diamond needles. A significant increase of electron emission current was detected under laser illumination. The nonlinear dependence of the emission current on the laser intensity and on the angle between the needle and the laser beam polarization axis suggests multi-photon emission processes. This interpretation is in agreement with electron spectroscopy measurements performed for electrons emitted at different bias voltages and different laser power levels and repetition rates. The remarkable feature of the diamond emitters is their stability under high average power of laser radiation. This provides a new highly efficient source of photoemitted electrons based on single-crystal diamond.
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http://dx.doi.org/10.1039/c9nr01001g | DOI Listing |
Materials (Basel)
December 2024
College of Mechanical Engineering, Zhejiang University of Technology, Hangzhou 310023, China.
As an environment-friendly material, graphene oxide nanosheet can effectively improve the polishing surface quality of single crystal diamond workpieces. However, the lubricating and chemical effects of graphene oxide nanosheets have an uncertain impact on the polishing material removal rate. In this paper, the graphene oxide-enhanced hybrid slurry was prepared with good stability.
View Article and Find Full Text PDFRev Sci Instrum
January 2025
Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
The Particle Time of Flight (PTOF) diagnostic is a chemical vapor deposition diamond-based detector and is the only diagnostic for measuring nuclear bang times of low yield (<1013) shots on the National Ignition Facility. Recently, a comprehensive study of detector impulse responses revealed certain detectors with very fast and consistent impulse responses with a rise time of <50 ps, enabling low yield burn history measurements. At the current standoff of 50 cm, this measurement is possible with fast 14 MeV neutrons from deuterium-tritium (DT) fusion plasmas.
View Article and Find Full Text PDFAdv Sci (Weinh)
December 2024
Department of Chemistry and Chemical Engineering, Chalmers University of Technology, Göteborg, SE-412 96, Sweden.
Carbazole-based self-assembled monolayer (SAM) materials as hole transport layers (HTL) have led organic solar cells (OSCs) to state-of-the-art photovoltaic performance. Nonetheless, the impact of the alkyl spacer length of SAMs remains inadequately understood. To improve the knowledge, four dichloride-substituted carbazole-based SAMs (from 2Cl-2PACz to 2Cl-5PACz) with spacer lengths of 2-5 carbon atoms is developed.
View Article and Find Full Text PDFChem Commun (Camb)
December 2024
Goethe University Frankfurt, Institute of Geosciences, Altenhöferallee 1, 60438 Frankfurt, Germany.
We have synthesized the first hydrous sp-carbonate by laser-heating Ba[CO], CO and HO in a diamond anvil cell at 40(3) GPa. The crystal structure of Ba[HCO][HCO][HCO][HCO] was determined by synchrotron single crystal X-ray diffraction. The experiments were complemented by DFT-based calculations.
View Article and Find Full Text PDFIUCrJ
January 2025
Department of Chemistry, Biological and Chemical Research Centre, University of Warsaw, Żwirki i Wigury 101, Warszawa, 02-089, Poland.
High-resolution single-crystal X-ray diffraction experiments on ZnSiO(OH)·HO hemimorphite were conducted at high pressure using diamond anvil cells at several different synchrotron facilities (ESRF, Elettra, DESY). Experimental data confirmed the existence of a previously reported phase transition and revealed the exact nature of the incommensurate modulation. We report the incommensurately modulated structure described in the (3+1)D space group Pnn2(0, β, 0)000.
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