Size effect in optical spectra of microcrystalline diamond powders and CVD films

Received: 24 March 1997/Accepted: 27 May 1997     

Structural manipulation of ultrathin organic films on metal surfaces: the case of decane thiol/Au(111)

3 (CH₂)₉]SH) have been adsorbed on Au(111) single crystals both via vacuum deposition and from an ethanolic solution. The epitaxial structure of the ultrathin organic films has been identified at room temperature via low-energy electron diffraction to be c(4×2)R30° for the solution grown film and rectangular c(23×) for the vacuum deposited film. These structures correspond to molecules adsorbed on the surface with their carbon chains flat on the surface (vacuum deposited) and nearly perpendicular (solution grown). It is demonstrated that this orientation can be changed reversibly in vacuum via either annealing the films or exposing them to additional gas. Received: 7 February 1997/Accepted: 27 May 1997     

Studies of interface structures of W films grown on patterned and bare Si(100) by TEM

+ Si(100) and bare Si(100) wafers by low pressure chemical vapour deposition (LPCVD) at 230–280 °C. The films were investigated by transmission electron microscopy (TEM). The cross-sectional TEM samples of W/Si(100) exhibited a fine scale interface roughness, which was attributed to the surface preparation. Irregular W plug structures were observed depending on the predeposition procedures. It was observed that an insufficient deposition of W films on the contact surface leads to the presence of aluminium around and underneath the plugs. This was observed by energy dispersive X-ray spectrometry (EDX). A study, using conventional electron diffraction, confirmed that no silicides formed at the interfaces of W-bare Si(l00) wafers. Received: 16 December 1996/Accepted: 6 May 1997     

On thickness dependence of electrical and optical properties of Te thin films

Received: 1 July 1997/Accepted: 6 August 1997     

Kinetics of evaporation of Cu beaded films on sapphire

-8 mbar were investigated by means of Auger electron spectroscopy in the temperature range 893–978 K. Measuring the time dependence of the normalized Auger intensity of Cu, we concluded that the process is controlled by a surface reaction at the perimeters of beads. From the temperature dependence of the initial and final parts of these curves we were able to determine the energy of activation of the desorption of Cu and of the surface reaction as well. Received: 9 June 1997/Accepted: 27 June 1997     

Correlation between density and structure. in boron nitride thin films by X-ray diffraction

* _ion=100 eV. Above E^* _ion the average density (deduced from X-ray reflectivity) shows a strong increase, indicating the sudden appearance of the cubic boron nitride phase consistent with the sp³ concentration deduced from IR absorption spectroscopy. The in-plane X-ray diffraction shows that this cubic phase consists of small nanocrystals of 70 Å linear size. Received: 26 November 1996/Accepted: 27 January 1997     

Coherent lattice dynamics of highly photo-excited tellurium

Received: 16 May 1997/Accepted: 16 May 1997     

Crystalline SiC thin film deposition by laser ablation: influence of laser surface activation

2 ) of the growing SiC film improved the film microstructure equivalent to an increase of the substrate temperature by 150–200 °C. Received: 18 August 1997/Accepted: 8 September 1997     

Lateral variation of quantum-well confinement energy in triangular-shaped dot-like structures grown by molecular beam epitaxy on patterned GaAs (311)A substrates

Received: 13 Oktober 1997/Accepted: 25 January 1998     

Photoredox laser chemistry of transition metal oxides

Received: 26 May 1997/Accepted: 17 July 1997     

Synthesis of carbon nitride films by low-power inductively coupled plasma-activated transport reactions from a solid carbon source

Thin films of carbon nitride were prepared by low-power inductively coupled plasma chemical vapor deposition from a solid carbon source by utilizing transport reactions. The maximum deposition rate achieved was 10 nm/min and depended mainly on the substrate position in the reactor. The nitrogen fraction in the films was not so sensitive to the process parameters and was at about 0.5 for all experiments as measured by Auger electron spectroscopy (AES) and elastic recoil detection (ERD) analysis. The chemical bonding structure studied by Fourier transform infrared (FTIR) spectroscopy and X-ray photoelectron spectroscopy (XPS) showed the presence of triple, double and single bonds between carbon and nitrogen atoms. Received: 12 May 1999 / Accepted: 12 May 1999 / Published online: 24 June 1999     

Heteroepitaxial growth of oxides on sapphire induced by laser radiation in the solid–liquid interface

2 O₃, Fe₂O₃ and MnO₂ on sapphire from an aqueous solutions of either CrO₃, FeCl₃, or KMnO₄, respectively, under laser irradiation of the interface sapphire/liquid. The interface is exposed through the sapphire substrate to the radiation of a copper vapor laser (wavelength of 510 nm). The etching of sapphire is accompanied by the deposition of oxide films, which are shown to grow epitaxially on the sapphire substrate, while the deposition of the polycrystalline oxide film occurs on a glass substrate under the same experimental conditions. Similarly, the epitaxial growth of cubic Fe₂O₃ and orthorhombic MnO₂ is observed, though their crystallographic structure is different from the hexagonal structure of sapphire. Received: 26 June 1997/Accepted: 7 July 1997     

Measuring the temporal intensity of ultrashort laser pulses by triple correlation

Received: 13 May 1997/Revised version: 1 August 1997     

Formation of amorphous layers by solid-state reaction. from thin Ir films on Si(100)

Received: 18 November 1997 / Accepted: 16 October 1998 / Published online: 24 February 1999     

A novel-high energy pulse compression system: generation of multigigawatt sub-5-fs pulses

Received: 28 February 1997 / Revised version: 2 May 1997     

Recurring dark states in Ramsey-type subrecoil cooling

Received: 30 May 1997/Revised version: 26 August 1997     

Al2O3 thin films by plasma-enhanced chemical vapour deposition using trimethyl-amine alane (TMAA) as the Al precursor

2 O₃ thin films by plasma-enhanced chemical vapour deposition (PECVD) using trimethyl-amine alane (TMAA) as the Al precursor. The thin films were deposited on both Si and quartz silica (SiO₂) substrates. Deposition rates were typically 60 Å min^-1 keeping the TMAA temperature constant at 45 °C. The deposited Al₂O₃ thin films were stoichiometric alumina with low carbon contamination (0.7–1.3 At%). The refractive index ranged from 1.54 to 1.62 depending on the deposition conditions. The deposition rate was studied as a function of both the RF power and the substrate temperature. The structure and the surface of the deposited Al₂O₃ thin films were studied using X-ray diffraction, atomic force microscopy (AFM) and scanning electron microscopy (SEM). Received: 20 May 1997/Accepted: 12 June 1997     

All-solid-state cavity-dumped sub-5-fs laser

Received: 19 March 1997/Revised version: 9 May 1997     

Photorefractive four-wave mixing with partially coherent light beams

Received: 11 April 1997/Revised version: 22 May 1997     

Porous layer effects on soft X-ray radiation emitted from a plasma generated by 130-fs laser pulses irradiating a porous silicon target

Received: 2 May 1997/Revised version: 17 October 1997