Via a specially widened anodic aluminum oxide (AAO) pore arrays, carbon nanodot arrays with uniform size and high density were obtained through filtered cathodic arc plasma (FCAP) technique. The AAO template was prepared in oxalic acid by multi-steps to get a specially enlarged opening which plays an important role in the deposition of nanodots. The morphology of the nanodots was studied by a field emission scanning electron microscopy (FESEM). The diameter of the as-prepared nanodot demonstrated here is about 100 nm at the bottom and less than 40 nm at the top, and the density was estimated to 1010 cm2. Field emission properties of the nanodot arrays were investigated and a low threshold field of 5.1 V/mm at 10 mA/cm2 was obtained. In this paper, the carbon nanodot arrays grown as replicas of the specially widened AAO template may support a strategy to realize the fabrication of nanodot arrays with various materials.

通过对阳极氧化铝(AAO) 模板进行特殊扩孔处理,消除了AAO 模板中带电阴离子对沉积碳离子的不良影响, 利用磁过滤阴极弧等离子沉积技术成功制备了非晶碳纳米尖点阵列膜. 场发射扫描电镜(FESEM) 分析表明,经过氧化和扩孔多步处理制备的AAO 模板具有特殊的开口结构,制备的非晶碳纳米尖点阵列完整地复制了AAO 模 板的孔道阵列结构,纳米点排列整齐有序,直径约100 nm ,密度达1010 cm- 2 ,样品的场发射测试显示,非晶碳纳米点阵列具有良好的电子发射性能,发射电流为10 mA/cm- 2时的阈值电场为317 V/μm.

The AlN:Mn hexagonal maze-like complex nanostructure was prepared via a simple thermal chemical vapor deposition process without structure-directing templates or catalysts. The optical property of the product was investigated by room-temperature photoluminescence (PL) measurement. Two emission bands centered at 490 nm and 600 nm, respectively. In addition to a familiar red-orange band centered at 600 nm originating from intra 3d-electrons transition of Mn2+ ion, another strong broad blue-green band around 490 nm is related to VAl 3−−3×ON+ defect complexes. The results indicate that the AlN:Mn maze-like complex nanostructure has a certain amount of Al vacancies, and the growth mechanism can be ascribed to nucleus arrangement and preferential growth.

Nanotip arrays of amorphous carbon with embedded hexagonal diamond nanoparticles were prepared at room temperature for use as excellent field emitters by a unique combination of anodic aluminum oxide (AAO) template and filtered cathodic arc plasma (FCAP) technology. In order to avoid nanopore array formation on the AAO surface, an effective multi-step treatment employing anodization and pore-widening processes alternately was adopted. The nanotips were about 100 nm in width at the bottom and 150 nm in height with density up to 1010 cm−2. Transmission electron microscopy investigation indicates that many nanoparticles with diameters of about 10 nm were embedded in the amorphous carbon matrix, which was proved to be hexagonal diamond phase by Raman spectrum and selected-area electron diffraction. There is no previous literature report on the field emission properties of hexagonal diamond and its preparation at room temperature under high-vacuum condition. The nanotip arrays with hexagonal diamond phase exhibit a low turn-on field of 0.5 V/μm and a threshold field of 3.5 V/μm at 10 mA/cm2. It is believed that the existence of hexagonal diamond phase has improved the field emission properties.

Growth of AlN hexagonal oriented complex nanostructures were induced by nucleus arrangement under certain conditions in a simple one step halide chemical vapor deposition (HCVD) system. The asprepared AlN nanostructures obtained at different positions from the Al source involve nanomaze, hexagonal nested arrays, hexagonal nanorod arrays with a small pit on the top of each rod and nanoparticle films, respectively. A relevant growth mechanism was suggested and interpreted in detail with a focus on the ‘‘nucleus arrangement’’ combined with preferential growth. Observations of nucleus arrangement events certify the rationality of this mechanism. We found that the variable ratio of AlCl3/ NH3 offers the power to mediate the arrangement of nucleus and crystal growth. There are some differences between the nucleus arrangement mechanism that we put forward here in the HCVD system and the oriented attachment that occurs in solution, because the former possesses a shorter mean free path of the nucleus.

Large scale Al-containing amorphous carbon (a-C:Al) nanotip arrays with uniform size and high density were obtained through filtered cathodic arc plasma (FCAP) technique via a specially widened anodic aluminum oxide (AAO) pore arrays as templates. The nanotip is about 100 nm in diameter at the bottom and 120 nm in height with density of 1010 cm−2. It was found that the sp3/(sp3 + sp2) ratio were 60.2%, 64.0%, 65.1% and 67.2% for Al content of 0.94 at%, 3.85 at%, 5.33 at% and 6.38 at%, respectively. The threshold field decreased to 0.32 V/m at 10 mA/cm2 and the maximum emission current density increased to 72 mA/cm2 at Al content of 6.38 at%. This kind of material will play a significant role in cold-cathode field emission display area.

ZnS hollow nanospheres with porous shells were successfully fabricated by a simple one-pot template-free hydrothermal route with the assistance of trolamine. The hollow nanospheres with a mean diameter of about 220 nm and the pore size of the porous shell of about 3.2 nm exhibit large BET surface areas of 129.9 m2 g21. The formation of ZnS hollow nanospheres was definitely driven by the well-known Ostwald ripening process. The morphology of the product could be controlled by adjusting the volume of trolamine in the ternary solution, which could influence the nucleation density and rate of the growing region during the initial stage of reaction. As synthesized, highly defective nanocrystalline ZnS exhibits a very strong defect-related green emission, which may pertain to the emission enhancement of the unique geometrical morphology of ZnS hollow nanospheres with a porous shell. The observed green PL emission of the wurtzite-type ZnS nanomaterials could provide an interesting application in the development of novel luminescent devices.