Details are given of an experimental study of microfabrication and characterization of a diode electron source using amorphous diamond (a-D) thin films. 〈100〈 n-type etched Si wafers with microscale-rough surface were used as cathode substrates. Filtered cathodic vacuum arc deposition technique was employed to coat a thin layer of a-D film on the Si substrate. Using the conventional photolithography, an array of well-defined diode structures with 20 μm gate diameter were formed. In addition, x-ray energy dispersive spectroscopy and atomic force microscopy were used to characterize the diode structure. Furthermore, the total emission current versus applied gate voltage of the diode electron source was measured. The physics of the emission process from the a-D diode was discussed.

宁生 许;峻聪 佘;Jian Chen;少芝 邓;军 陈

Applied Physics Letters

2000-10-30

Nanocrystalline WO₃ thin films were prepared using a colloid chemistry method. The particle size and crystallinity of the films were tailored by controlling the concentration of oxalic acid in the colloid solution. The growth process and microstructure of the films were observed with a transmission electron microscope (TEM). Using ultraviolet-visible absorption spectrum (UVAS), the dependence of photochromic behavior on crystallite size was investigated. Exposure of the films to ultraviolet light makes the films blue in color.

牧 孙;宁生 许;Y. W. Cao;建年 姚;恩哥 王

Journal of Materials Science Letters

2000-8

Tungsten oxide nanowire is a very promising cathode nanomaterial, which has exhibited good emission properties. In most preparation methods, the growth temperature is higher than 800 °C, which is too high for application in field emission display which used glass as the substrate. Moreover, the selected-area growth of the tungsten oxide is also a challenge. Here we provide a simple method to fabricate patterned WO₂ nanowire at 550 °C. The result is of significance for their applications in field emission display.

Li Li;Fei Liu;Tongyi Guo;Shunyu Jin;Haibo Gan;军 陈;少芝 邓;宁生 许

2011

Considering that the actual terrestrial solar irradiance is dynamically changing with the atmosphere, the overall efficiencies of most current solar cells are much lower than the reported static values that are based on a standard solar spectrum. The realizations of solar cells, which can maintain high efficiency under variable solar irradiance, are necessary for further improvement of solar energy conversion. In this work, a metal-insulator-semiconductor (MIS) structure based photon-enhanced thermionic energy converter (PETEC) has been proposed for intrinsic adaptive full spectrum solar energy conversion. The basic idea is to form the thermionic electron with desired energy by the photon-enhanced thermal tunneling process. Investigations on its fundamental performance indicate that the MIS-PETEC can have an overall output energy improvement of at least 0.8%, 2.5%, and 3% in typical sunny, rainy, and cloudy days compared to the normal PETEC. Additionally, the total output energy over a year can be improved by at least 3%. These results offer an alternate technique for intrinsic adaptive full spectrum solar energy conversion, which is helpful for the development of next generation high performance solar cells.

Yicong Chen;少芝 邓;宁生 许;军 陈

Applied Physics Letters

2020-2-10

A novel approach for preparation of europium (III)-doped yttrium oxide (Y₂O₃:Eu³⁺) nanoparticles by microemulsion-microwave heating was reported in this paper. Y₂O ₃:Eu³⁺ nanoparticles were successfully obtained by microwave-heating the as-prepared particles of yttrium hydroxide and europium hydroxide, formed in a reaction between Y(NO₃)₃-Eu(NO ₃)₃ and NH₃·H₂O in the reverse microemulsion composed of Triton X-100, n-hexanol, cyclohexane and water. Field-emission scanning electron microscopy (FE-SEM) and powder X-ray diffraction (XRD) results indicated that the resultant nanoparticles showed a narrow size distribution, small size (20-30 nm) and spherical shape. The ratios of Eu to Y in the products, determined by energy dispersive spectroscopy (EDS), were in good agreement with those of the feed. The nanoparticles emitted much strong red light at 611 nm under UV excitation, especially around 255 nm. Furthermore, this novel method required a very short heating-time and the energy consumption was much smaller compared with conventional heating ways.

Qi Pang;Jianxin Shi;Yu Liu;Desong Xing;Menglian Gong;宁生 许

Materials Science and Engineering B: Solid-State Materials for Advanced Technology

2003-9-25

Tungsten oxide is well known as an excellent semiconductor material and shows good electrochromic and photochromic properties ^[1-3]. Due to their high aspect ratio, tungsten oxide nanowires have attracted intensity interest as potential cold cathode materials recently^[4]. However, there are some difficulties in the practical application of such nanowire arrays, for example, it is hard to prepare the good uniformity nanowires on large area substrate. In this paper, we report a very simple synthesis approach to fabricate tungsten oxide nanowire arrays on large area silicon substrate(10 × 15 mm²). A set of tungsten wires was used as the tungsten source, the silicon substrates were placed on a holder ∼2 mm beneath the wires. The chamber was first pumped to 1 × 10^-2 Torr, then high purity argon was introduced to the chamber, and the tungsten wires were heated by passing current through them sequentially. When the temperature of tungsten wires was about 1200 , hot tungsten wires surface was oxidized by the remained oxygen of the vacuum chamber. As a result, the tungsten oxide NW arrays were grown on silicon substrates. It was catalyst free during the synthesis process. The scanning electron microscopy (SEM) images showed that the nanowires were well aligned and vertically oriented to substrate surface, and the range of the nanowires diameter was in between 40 nm and 100 nm, the typical length of them about 3.5 μm (Fig l(a) and Fig l(b)). The X-ray diffraction (XRD) analyses showed the component of the nanowires was W₁₈O₄₉ (Fig 2). The field emission measurement of the nanowire arrays showed the turn-on field with about 9 MV/m (Fig 3), which is defined as the macroscopic field required to produce a current density of 10 μA/cm². The relative high turn-on fields maybe due to the electrostatic screening effect^[5] caused by the high density of tungsten oxide nanowire arrays.

L. F. Chi;少芝 邓;军 陈;峻聪 佘;宁生 许

2005

A1N nanowires have low electron affinity, which has been considered as one of the ideal cathode materials in future. Although many methods have been developed to prepare A1N nanowires with different morphologies, little effort is found to focus on the patterned growth technique, which has limited their applicaitions. Here we provide a ceramic template method to fabricate patterned A1N nanowire arrays, which have better field emission performance than the continuous nanowire film.

Zanjia Su;Fei Liu;Lifang Li;Tongyi Guo;Haibo Gan;军 陈;少芝 邓;宁生 许

2011

The development of high performance nano-electron-emitter arrays with well reliability still proves challenging. Here, we report a featured integrated nano-electron-emitter. The vertically aligned nano-emitter consists of two segments. The top segment is an intrinsically lightly n-type doped ZnO nano-tip, while the bottom segment is a heavily p-type doped Si nano-pillar (denoted as p-Si/ZnO nano-emitter). The anode voltage not only extracted the electron emission from the emitter apex but also induced the inter-band electron tunneling at the surface of the p-Si/ZnO nano-junction. The designed p-Si/ZnO emitter is equivalent to a ZnO nano-tip individually ballasted by a p-Si/ZnO diode and a parasitic tunneling field effect transistor (TFET) at the surface of the p-Si/ZnO junction. The parasitic TFET provides a channel for the supply of emitting electron, while the p-Si/ZnO diode is benefit for impeding the current overloading and prevent the emitters from a catastrophic breakdown. Well repeatable and stable field emission current were obtained from the p-Si/ZnO nano-emitters. High performance nano-emitters was developed using diamond-like-carbon coated p-Si/ZnO tip array (500 × 500), i.e., 178 μA (4.48 mA/cm 2) at 75.7 MV/m.

Tao Cao;Laitang Luo;Yifeng Huang;Bing Ye;峻聪 佘;少芝 邓;军 陈;宁生 许

Scientific Reports

2016-9-22

A convenient fabrication technique for samarium hexaboride (SmB⁶) nanostructures (nanowires and nanopencils) is developed, combining magnetron-sputtering and chemical vapor deposition. Both nanostructures are proven to be single crystals with cubic structure, and they both grow along the [001] direction. Formation of both nanostructures is attributed to the vapor-liquid-solid (VLS) mechanism, and the content of boron vapor is proposed to be the reason for their different morphologies at various evaporation distances. Field emission (FE) measurements show that the maximum current density of both the as-grown nanowires and nanopencils can be several hundred μA/cm², and their FN plots deviate only slightly from a straight line. Moreover, we prefer the generalized Schottky-Nordheim (SN) model to comprehend the difference in FE properties between the nanowires and nanopencils. The results reveal that the nonlinearity of FN plots is attributable to the effect of image potential on the FE process, which is almost independent of the morphology of the nanostructures. All the research results suggest that the SmB⁶ nanostructures would have a more promising future in the FE area if their surface oxide layer was eliminated in advance.

Xun Yang;Hai Bo Gan;Yan Tian;宁生 许;少芝 邓;军 陈;Huanjun Chen;世东 梁;Fei Liu

Chinese Physics B

2017-11

An electron spectroscopy technique, employing a plane-parallel electrode geometry with an anode probe hole, has been used to make a detailed study of how the Fowler-Nordheim plot of a single emission site varies with gap separation d. After correcting for the gap field in the vicinity of the probe hole, it has been established that the field enhancement or β factor of the site does not in fact exhibit a dependence on the total gap voltage over the range 0.4 ≾ d ≾ 1.0 mm.

宁生 许;R. V. Latham

IEEE Transactions on Electrical Insulation

1989-12