摘要:

Scanning Force Microscopy (SFM) offers new possibilities for surface studies on insulators, but still needs work on interpretation of the images and on the limits of what may or may not be measured. Experimental and theoretical investigations of tip-sample interactions and interpretation of images at the atomic length scale are discussed. Observations have been made on pure crystals, samples doped with charged defects, and mixed crystal alloys. The SFM has proved useful in investigations of radiation damage on insulators at mesoscopic scales, using bothex situandin situirradiation.

ISSN:1042-0150    

DOI:10.1080/10420159508222683

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

CaF2and SrF2films grown on Si(111) by molecular beam epitaxy were studied by Brillouin spectoscopy method. The measured velocities of surface acoustic waves are in close agreement with those calculated within simple model of a layered structure. The only discrepancy was a decrease of the velocity in CaF2films of about 100 nm thick and was attributed to the different distribution of the defects arizing at the early stages of the growth modes at the beginning of CaF2and SrF2epitaxy on Si(111).

ISSN:1042-0150    

DOI:10.1080/10420159508222684

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

Propagation of pseudo surface modes, PSMs, propagating on SrF2epitaxial layers deposited on GaAs(111) was studied by means of Brillouin spectroscopy. A lowering of 3 ÷ 77% of the velocity values of the PSMs was detected in case of leaky modes of a relatively strong leakage. The observed deviations of the velocity of the PSMs are connected with the presence of a roughness region of fluoride/GaAs(111) interface extending on several nm.

ISSN:1042-0150    

DOI:10.1080/10420159508222685

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

Electron irradiation of CaF2with 2 keV electrons causes metallization of the surface and near surface layers by the formation of colloids. Colloids on the surface are significantly larger than those in the bulk indicating a higher mobility of defects on the surface. Optical spectroscopy on extinction bands of bulk colloids reveals Ostwald ripening as the driving force for aggregation, while scanning force microscopy results suggest that similar processes dominate the early stages of surface colloid formation.

ISSN:1042-0150    

DOI:10.1080/10420159508222686

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

It was found from the IR and UV-visible spectra, that the ion implantation into polymers results in the breakage of molecular chain, creation of double bonds and oxidation, which is connected with formation of carbonyl groups. The considerable increase of the electrical conductivity after the ion implantation was observed in all studied polymers. This increase of the conductivity was essentially caused by the increase of conjugated double bonds. In unpolar polymers, the increase of surface free energy resulting in enhancement of polarity of unpolar polymer was found.

ISSN:1042-0150    

DOI:10.1080/10420159508222687

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

As detected by Auger electron spectroscopy (AES), the interaction of a pure (100) LiF surface with an electron beam induces a loss of fluorine. Lithium atoms are oxidized in the vacuum ambient and the formation of lithium oxide Li2O has been characterized using electron energy loss spectroscopy (EELS) by typical structures at 18.6 and 10 eV. The loss of fluorine is associated with a decrease of the positive surface potential. The cathodoluminescence (CL) emissions detected in the 250–900 nm wavelength range at 3.8, 3.1, 2.3 and 1.9 eV have been attributed to F, F3+and F2centers.

ISSN:1042-0150    

DOI:10.1080/10420159508222688

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

A new class of heterostructures such as semiconducting film coatings of the iron-garnet substrates is investigated on the issue of their physical properties. It is proven that unlike a world of difference in their crystal lattice parameters, heterostructures like ZnSe-GGG and ZnSe-YIG possess satisfactory mechanical properties and crystal structure.

ISSN:1042-0150    

DOI:10.1080/10420159508222689

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

In the present paper the investigation of optical properties in ZnSe single crystals from action by the infrared light radiation is provided. It is shown that laser light induced thermochemical reaction, of a certain type, harnesses a metallization effect at the sample surface.

ISSN:1042-0150    

DOI:10.1080/10420159508222690

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

An investigation of Raman scattering in CdSe nanocrystals embedded in oxide glass matrix under resonant excitation has been accomplished. First we observe the dependence of both the longitudinal optical phonon and the low frequency scattering energies with the excitation wavelength which is explained in terms of size selective excitation. A peculiar attention is given to the behaviour of low-frequency spectra and selection rules due to resonance effects are reported. Most of the first harmonics of the different predicted vibration modes have been observed and a qualitative attempt has been made to link the observed modes with the excited electronic levels.

ISSN:1042-0150    

DOI:10.1080/10420159508222691

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

Samples of nanocrystalline Cu doped ZnO have been prepared and characterised by several techniques including chemical analysis, X-ray powder diffraction and X-Ray absorption spectra (EXAFS). The particle sizes are typically less than 100 Å on the largest diameter. The diffraction results show that lightly doped samples, less than 10 mole per cent Cu, are single phase with the ZnO crystal structure. The EXAFS results indicate that although the Zn2+ions occupy normal cation sites the Cu2+ions are in highly disordered sites, suggesting that there is possible surface aggregation. Gas sensing experiments show a good response to low ppm concentrations of toluene vapour.

ISSN:1042-0150    

DOI:10.1080/10420159508222692

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor