Point sources exhibit low threshold electron emission due to local field enhancement at the tip. The development and implementation of tip emitters have been hampered by the need to position them sufficiently apart to achieve field enhancement, limiting the number of emission sites and therefore the overall current. Here we report low threshold field (< 0.1V/m) emission of multiple electron beams from atomically thin edges of reduced graphene oxide (rGO). Field emission microscopy (FEM) measurements show evidence for interference from emission sites that are separated by a few nanometers, suggesting that the emitted electron beams may be coherent.Based on our high-resolution transmission electron microscopy, infrared spectroscopy and simulation results, field emission from the rGO edge is attributed to a stable and unique aggregation of oxygen groups in the form of cyclic edge ethers. Such closely spaced electron beams from rGO offer prospects for novel applications and understanding the physics of linear electron sources.
A novel class of low molecular-weight organic resist materials for nanometer lithography, 1,3,5-tris[4-(4-toluenesulfonyloxy)phenyl]benzene (TsOTPB) and 4,4′,4″-tris(allylsuccinimido) triphenylamine (ASITPA), was designed and synthesized. TsOTPB with a glass-transition temperature (Tg) of 64 °C and ASITPA with a Tg of 80 °C were found to function as positive and negative resists, respectively, enabling the fabrication of 150 and 70 nm line patterns on exposure to an electron beam at 50 keV.
Maskless laser patterning of indium tin oxide thin films for flat panel display applications was studied as a function of wavelength using different harmonics of a diode-pumped Q-switched Nd:YLF laser. Electrically isolating lines could be written at all wavelengths used. However, while lines written at the infrared and the visible wavelengths exhibited a ripplelike morphology due to incomplete material removal, ultraviolet laser irradiation produced residue-free etch lines with superior smoothness even at higher scan speeds. The threshold fluences for material removal at different wavelengths were found to correlate with the optical properties of the indium tin oxide film. In addition, numerical simulations of laser-induced temperature rise yielded peak surface temperatures well above the vaporization temperature of the indium tin oxide film, indicating that, at all wavelengths studied, material removal occurs via thermal vaporization. The calculations also revealed that the absorption of the ultraviolet laser light by the glass substrate is the key factor for the residue-free removal of the indium tin oxide film. Moreover, using a flashlamp-pumped Nd:yttrium-aluminum-garnet laser and a galvanometric scanning system, high process speeds in excess of 1 m/s could be achieved.
Patterning characteristics of indium tin oxide thin films using different wavelengths of a diode-pumped Q-switched Nd:YLF and a flashlamp-pumped Nd:YAG laser have been studied. While a ripplelike structure in the etched line was formed due to incomplete material removal when the first harmonic of the Nd:YLF or Nd:YAG laser was used, a residue-free line could be obtained using the fourth harmonic of the Nd:YLF laser even at higher scan speeds. The observed differences in the morphology could be attributed to different absorption characteristics at the infrared and ultraviolet wavelengths. High process speeds in excess of 1 m/s could be achieved.
Abstrad. We report on angular distribution meaSuremene in 50 keV Ar15+ on Ar chargetransfer collisions. Distributions w m p n d i n g to the production of up to quintuplysharged recoils were oblained, and compared to the predictions of the molecular classical overbarrier model (MCBM) of Niehaus under different assumptions. We found no evidence that the contributions of the tightiy bund target elenrons are overestimated by the MCBM, in c o n m with the observations of D m d el a1 and Guillemot el a/. 'Ex previously r e p l e d Q-values of Ali erof for the s m processes were funher compared to the model predictions under similar assumptions and the e n d s were found U) be consistent with those of the angular distributions.
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