E. V. Rakova

Growth of diamond particles on sharpened silicon tips for field emission

Abstract Preparation and field-emission characteristics of silicon tips coated by diamond particles are described. The particles grew by a hot-filament CVD process preferentially on the very ends of the tips. An explanation is given for the preferential deposition based on the idea that the real temperature of the ends is markedly, about 200 °C, greater than the average temperature of the tips. Field-emission measurements showed that diamond-coated silicon tips can give currents as large as 500 μA before they are destroyed, at least one order of magnitude larger than uncoated silicon tips. The temporal stability of the emission current was high.

Heteroepitaxial deposition of single-crystal diamond particles on sharpened Si tips

Abstract Heteroepitaxial single-crystal diamond particles were formed on sharpened Si tips in a hot-filament CVD process at increased content of atomic hydrogen in the vapor phase.

Specific features of the growth of AIIBVI films on (0001)Al2O3 substrates

The structure and orientation of CdTe and ZnO films on sapphire have been investigated for different techniques of pregrowth substrate treatment. Polycrystalline CdTe films are found to grow of substrates unannealed or annealed in vacuum at a residual pressure P < 0.13 Pa. Epitaxial CdTe films with the sphalerite cubic structure, oriented parallel to the substrate by the (111) plane, grow on substrates annealed in air at a temperature of 1000°C or more and having a system of smooth terraces and steps on the surface. For ZnO films with a wurtzite hexagonal structure obtained by magnetron sputtering, a similar correlation between the structural quality and the regime of treatment of sapphire substrates is observed. It is shown that thermal annealing of (0001) sapphire plates in air is the optimal way of substrate preparation for growing epitaxial ZnO films with the base orientation. The obtained epitaxial CdTe films contain a certain amount of structural defects (mosaicity and twins), while the epitaixal ZnO films treated in the same way are close to perfect.

Growth of diamond particles on sharpened Si tips

Growth of diamond particles on sharp silicon tips in a hot-filament CVD process was investigated. Highly preferential deposition of the particles on the ends of the tips has been found. An explanation is given for the phenomenon based on the idea that the ends have an increased temperature due to localized recombination of hydrogen, involved in the process, on the tips. HRTEM and electron diffraction investigations of the initial stages of the growth have demonstrated a direct localized epitaxial growth of diamond on silicon.

Growth of crystalline ZnO films on the nitridated (0001) sapphire surface

The surface morphology and structure of (0001) sapphire substrates subjected to thermochemical nitridation in a mixture of N2, СО, and Н2 gases are investigated by electron and probe microscopy and X-ray and electron diffraction. It is shown that an aluminum nitride layer is formed on the substrate surface and heteroepitaxial ZnO films deposited onto such substrates by magnetron sputtering have a higher quality when compared with films grown on sapphire.

Sapphire substrates with a regular surface relief

The lithography-free technique is proposed to obtain a regular relief in the form of a regular 2D system of 25-nm protrusions on a sapphire plate surface. The use of grid masks allows one to form a regular relief on the sapphire substrates of arbitrary area. The structure of crystal films formed by the sputtering of metal aluminum onto sapphire substrates with subsequent oxidation and annealing is thoroughly investigated and compared with the nanostructured (0001) sapphire wafer surface in the form of regular steps up to 5 nm in height with atomically smooth terraces.

Influence of ensembles of gold nanoparticles on the growth of ZnO on the sapphire (0001) surface

Gold is deposited on sapphire (0001) substrates by vacuum sputtering to form an ensemble of nanoparticles on the surface. Then the substrates are transferred to a magnetron sputtering chamber to be heated to 650°C and coated by a ZnO layer. The resulting layers are investigated by scanning electron microscopy, atomic force microscopy, electron diffraction, and photoluminescence. It is established that the Au sublayer ensures a higher quality of the ZnO structure and enhances photoluminescence. The differences in the morphology of ZnO structures is explained by the Au aggregation during substrate heating before ZnO deposition.

Nucleation and growth of crystalline diamond particles on silicon tips

The data on the deposition, structure, and electric properties of crystalline diamond particles at silicon tips grown on single-crystal silicon substrates obtained over the last decade, mainly at the Institute of Crystallography of the Russian Academy of Sciences, have been reviewed. It is shown that silicon emitters coated with crystalline diamond are highly electrically stable. They are used to prepare long-life cathodoluminescence light sources.

Diamond Particles on Silicon Tips: Preparation, Structure, and Field Emission Properties

Negative electron affinity (NEA) of diamond as a property inherent in the material is known for a time [1]. Quite recently, the property has attracted a strong interest for applications in vacuum microelectronics and in other fields of modern science and technology [2]. Tentative applications in field-emission displays (FED) is probably one of the most popular.