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The as-grown structure of electrochemically synthesized titania nanotube arrays is investigated by scanning electron microscope (SEM) in combination with transmission electron microscope (TEM) as well as X-ray diffraction (XRD). The analysis reveals a preferred growth direction of the nanotubes relative to the substrate surface and the well control on the nanotube arrays morphology. The crystal structure of the anatase phase is detected and exists in the tube walls without any thermal treatment, which makes it possible to realize the application of as-formed TiO2 nanotubes avoiding the degradation of the nanotube structures when sintering. In addition, a new growth, layered model of the anodic TiO2 nanotubes is presented to obtain further understanding of the growth mechanism.

Plasma anodic oxidation/nitridation of Ge(111) wafer was carried out in a plasma atmosphere of oxygen or an ammonia/nitrogen mixture. The plasma was excited by a high-frequency (0.5 MHz) electromagnetic field. The chemical and physical properties of the grown films were analysed using Auger electron spectroscopy, X-ray photoelectron spectroscopy, infrared spectrophotometry and high-frequency C-V characterization. The results show that the refractive index (1.60 +or- 0.02), chemical composition (O/Ge approximately= 2.1) and infrared absorption peaks (560 cm-1 and 870 cm-1 of the oxygen plasma anodized films are very similar to those of vitreous GeO2, and that an oxygen plasma anodized film on a germanium substrate has excellent insulating and interface-state properties. It is also shown that after the nitridation processing of an oxygen plasma anodized film, the solubility of the film was greatly diminished due to the formation of the germanium oxynitride overlayer. For plasma anodic nitrided films on Ge, the refractive index is 2.10 +or- 0.02 at the growth temperature of 540-700 degrees C and the bulk composition is N/Ge approximately= 1.26. There is a broad absorption band (730-780 cm-1) and a weak peak (910 cm-1) in the IR spectrum of the plasma anodic nitrided film. These absorption peaks are associated with the alpha -phase germanium nitride and beta -phase germanium nitride in the film.

This paper reports the techniques of growing uniform native oxide films on Ge(111) wafers by the method of high-frequency (500 kHz) oxygen-plasma anodization and of preparing the Ge-MOS structure using oxygen-plasma-anodized (OPA) film as gate insulator. The high-frequency C-V characteristics of prepared Ge-MOS structures show that the fixed oxide charge density near the OPA film-Ge interface is about 1011 cm-2. It is also shown that the breakdown electrical field intensity of OPA film is of the order of 106V cm-1. These results indicate that it is feasible to prepare Ge-MOS structures using the plasma-anodized film on germanium.

Anodic nitridation of a germanium wafer was carried out successfully in a plasma of ammonia:nitrogen excited by a high-frequency (500 kHz) electromagnetic field. The transmittances of the plasma-nitrided (PN) films on Ge(111) were measured by a Nicolet 170 SX Fourier transform infrared spectrometer and an IR-450S type infrared spectrophotometer. The infrared absorption bands of the beta -phase PN film on Ge are at 910 cm-1 (w) and 780 cm-1 (s) in the range of 4000-400 cm-1. The absorption bands of the two-phase ( alpha + beta ) growing PN film are at 910, 780 and 730 cm-1.