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Field-enhancement Factor (field-enhancement + factor)

Distribution by Scientific Domains
Polymers and Materials Science100%

Selected Abstracts

Template Deformation-Tailored ZnO Nanorod/Nanowire Arrays: Full Growth Control and Optimization of Field-Emission

ADVANCED FUNCTIONAL MATERIALS, Issue 19 2009
Haibo Zeng
Abstract Here, a facile and effective route toward full control of vertical ZnO nanorod (NR)/nanowire (NW) arrays in centimeter-scale areas and considerable improvement of field-emission (FE) performance is reported. Controlled deformation of colloidal crystal monolayer templates is introduced by heating near glass-transition temperature. The NR/NW density, uniformity, and tapering were all adjusted through selection of template size and deformation, and electrolyte composition. In line with the adjustments, the field-emission performance of the arrays is significantly improved. A low turn-on electric field of 1.8,V µm,1, a field-enhancement factor of up to 5,750, and an emitting current density of up to 2.5,mA cm,2 were obtained. These improved parameters would benefit their potential application in cold-cathode-based electronics. [source]

Characterization, Cathodoluminescence, and Field-Emission Properties of Morphology-Tunable CdS Micro/Nanostructures

ADVANCED FUNCTIONAL MATERIALS, Issue 15 2009
Tianyou Zhai
Abstract High-quality, uniform one-dimensional CdS micro/nanostructures with different morphologies,microrods, sub-microwires and nanotips,are fabricated through an easy and effective thermal evaporation process. Their structural, cathodoluminescence and field-emission properties are systematically investigated. Microrods and nanotips exhibit sharp near-band-edge emission and broad deep-level emission, whereas sub-microwires show only the deep-level emission. A significant decrease in a deep-level/near-band-edge intensity ratio is observed along a tapered nanotip towards a smaller diameter part. This behavior is understood by consideration of defect concentrations in the nanotips, as analyzed with high-resolution transmission electron microscopy. Field-emission measurements show that the nanotips possess the best field-emission characteristics among all 1D CdS nanostructures reported to date, with a relatively low turn-on field of 5.28,V µm,1 and the highest field-enhancement factor of 4,819. The field-enhancement factor, turn-on and threshold fields are discussed related to structure morphology and vacuum gap variations under emission. [source]

Field Emission and Cathodoluminescence of ZnS Hexagonal Pyramids of Zinc Blende Structured Single Crystals

ADVANCED FUNCTIONAL MATERIALS, Issue 3 2009
Zhi-Gang Chen
Abstract Single-crystal hexagonal pyramids of zinc blende ZnS are fabricated by facile thermal evaporation in an ammonia atmosphere at 1150,°C. It is found that ZnS pyramids grow along the [111] crystal axis and possess a sharp tip with a diameter of ,10,nm and a micrometer-sized base. The structural model and growth mechanism are proposed based on crystallographic characteristics. This unique ZnS pyramid structure exhibits a low turn-on field (2.81,V µm,1), a high field-enhancement factor (over 3000), a large field-emission current density (20,mA cm,2), and good stability with very small fluctuation (0.9%). These superior field-emission properties are clearly attributed to the pyramid morphology, with micrometer-sized bases and nanotips, and high crystallinity. Moreover, a stable UV emission of 337,nm at room temperature is observed and can be ascribed to the band emission of the zinc blende phase. These results suggest that the ZnS hexagonal pyramids can be expected to find promising applications as field emitters and optoelectronic devices. [source]

ZnS Branched Architectures as Optoelectronic Devices and Field Emitters

ADVANCED MATERIALS, Issue 21 2010
Zhi-Gang Chen
A unique ZnS branched architecture was fabricated by a facile thermal evaporation method. Stable UV emission at 327,nm and superior field emission with a low turn-on field, a high field-enhancement factor, a large current density, and small fluctuation were observed. [source]

Ultrafine ZnS Nanobelts as Field Emitters,

ADVANCED MATERIALS, Issue 18 2007
S. Fang
Single-crystalline, narrow-size- distribution ultrafine ZnS nanobelts (see figure), revealing a notable quantum-confinement effect, have been synthesized at a high yield by controlling the evaporation and agglomeration rates. Field-emission measurements show ultrafine ZnS nanobelts are very good field emitters with a low turn-on field and high field-enhancement factor. [source]