High-Performance Electron Field Emitters and Microplasma Cathodes Based on Conductive Hybrid Granular Structured Diamond Materials

Abstract

High-performance diamond electron field emitters (EFEs) with extremely low turn-on field (E = 1.72 V/μm) and high current density (1.70 mA/cm at an applied field of 3.86 V/μm) were successfully synthesized by using a modified two-step microwave plasma chemical deposition process. Such emitters possess EFE properties comparable with most of carbon- or semiconductor-based EFE materials, but with markedly better lifetime stability. The superb EFE behavior of these materials was achieved owing to the reduction in the diamond-to-Si interfacial resistance and the increase in the conductivity of the bulk diamond films (HBD) via the applications of high bias voltage during the preparation of the ultrananocrystalline diamond (UNCD) primary layer and the subsequent plasma post-treatment (PPT) process, respectively. The superior EFE properties along with enhanced robustness of HBD films compared with the existing diamond-based EFE materials rendered these materials of greater potential for applications in high brightness display and multifunctional microplasma.

Origin of Conductive Nanocrystalline Diamond Nanoneedles for Optoelectronic Applications

“…Among carbon based field emitters, diamond possesses excellent FEE characteristics owing to its strong bonding structure, low electron affinity, good electrical and thermal conductivities, and utmost hardness to withstand ion bombardment. 9,10 During the 1990s, the diamond based FEE studies were accomplished on materials deposited using CH4/H2 plasmas, which resulted the deposition of microcrystalline diamond (MCD) films of grain sizes ranging from 0.1 µm to several tens of microns. The large diamond grains, whose properties resemble those of monocrystalline diamond, have a large electronic band gap hindering the FEE behavior of the MCD films because of a shortage of the electrons required for field emission.…”

“…Field electron emitters with applicable electron emission characteristics, for example, low turn-on field, steady and high current density, and large field enhancement factor, find potential applications as flat panel displays, cathodes in X-rays, vacuum microelectronic devices, and microplasma devices. − Nanocarbon materials, including carbon nanotubes, graphene, tetrahedral amorphous carbon (a-C), diamond-like carbon, and diamond, have been comprehensively investigated for the exploitation of field electron emission (FEE). Among carbon-based field emitters, diamond possesses excellent FEE characteristics owing to its strong bonding structure, low electron affinity, good electrical and thermal conductivities, and utmost hardness to withstand ion bombardment. , …”

Enhancement of UV Photodetection Properties of Hierarchical Core–Shell Heterostructures of a Natural Sericin Biopolymer with the Addition of ZnO Fabricated on Ultra-Nanocrystalline Diamond Layers

“…The Ar-rich UNCD films also exhibit outstanding stability compared with that of carbon nanotube (CNT) composites, graphenes, and the currently existing semiconducting oxide materials. Also, it has recently been demonstrated that Ar-rich UNCD films are promising materials for practical applications being able to survive longer operation times at high temperatures and in high-vacuum environments. , …”

“…Also, it has recently been demonstrated that Ar-rich UNCD films are promising materials for practical applications being able to survive longer operation times at high temperatures and in high-vacuum environments. 3,4 Sericin is a natural polymer found in the bioindustrial waste extracted from silk cocoons during the degumming process. A lot of textile manufacturers are producing silk products on a large scale.…”

Dependence of Optimum Thickness of Ultrathin Diamond-like Carbon Coatings over Carbon Nanotubes on Geometric Field Enhancement Factor

“…Coating CNTs with wide bandgap (WBG) materials, which are able to reduce the effective work function and provide mechanical protection for the sharp emitters, has been considered as one of the most successful approaches to increase the stability of CNTs’ FE current while keeping a low applied driving voltage. − Besides widely used oxides such as silicon dioxide, magnesium oxide, zinc oxide, or titanium dioxide, sp 3 -bonded carbon materials are strong candidates for this coating, for instance, ultranano­crystalline diamond (UNCD) − or diamond-like carbon (DLC) , films. It has been undoubtedly verified that sp 3 coatings stabilize, and even improve, the CNT FE currents, − owing to their favorable properties, such as low or even negative electron affinity (LEA or NEA), mechanical strength, and radiation tolerance. , However, the FE enhancement induced by sp 3 coatings, which refers to a decrease of turn-on fields hereinafter, was not inevitable. − , It has been suggested by extensive studies that there is a relationship between the coating thicknesses and turn-on fields.…”