Publications by authors named "Katsuhisa Murakami"
We have succeeded in obtaining BaSnO perovskite thin films with remarkable near-infrared luminescence by van der Waals growth. The films were grown on quartz glass substrates by pulsed laser deposition using hexagonal boron nitride as the seed layer, and their crystallinity was confirmed by X-ray diffraction and cross-sectional transmission electron microscopy. The near-infrared emission of the grown film exhibited a broad emission peak centered at 920 nm.
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- The study focuses on the low-temperature synthesis of thick multilayered hexagonal-boron nitride (h-BN) on quartz and silicon substrates to improve electronic devices using 2D materials.
- Using inductively coupled plasma-enhanced chemical vapor deposition at temperatures between 400 and 500 °C, researchers achieved h-BN thickness over 5 nm, with enhanced crystal quality through optimized synthesis parameters.
- The synthesized h-BN exhibited a band gap of about 5.8 eV and comparable Raman peak characteristics to commercially available h-BN, indicating potential for applications in high-performance electronics.
Graphene-oxide-semiconductor (GOS) planar-type electron emission devices with a hexagonal boron nitride (h-BN) protective layer have demonstrated improved oxidation resistance while maintaining their emission performance. The devices with a monolayer or a multilayer (13 nm in thickness) h-BN protective layer can emit electrons even after oxygen plasma exposure (ashing). Remarkably, the device with a monolayer h-BN was able to emit electrons with a maximum efficiency of 11% after a 4-min ashing, showing that a thin h-BN protection layer can provide oxygen tolerance to GOS devices without a significant emission loss.
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- A new planar electron emission device using a graphene/hexagonal boron nitride (h-BN)/n-Si structure is created to achieve highly monochromatic electron emission from a flat surface.
- The h-BN layer acts as an insulator, significantly reducing electron inelastic scattering, leading to an energy spread of 0.28 eV, similar to traditional tungsten field emitters.
- The device demonstrates a maximum emission current density of 2.4 A/cm, indicating that the graphene/h-BN combination is effective for producing a high-quality electron beam suitable for various applications.
Nanoscale characterization of TiO(2) films grown by atomic layer deposition on RuO(2) electrodes.
ACS Appl Mater Interfaces
February 2014
Topography and leakage current maps of TiO2 films grown by atomic layer deposition on RuO2 electrodes using either a TiCl4 or a Ti(O-i-C3H7)4 precursor were characterized at nanoscale by conductive atomic force microscopy (CAFM). For both films, the leakage current flows mainly through elevated grains and not along grain boundaries. The overall CAFM leakage current is larger and more localized for the TiCl4-based films (0.
View Article and Find Full Text PDFPoint 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.
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