Application of nanotechnology products requires identification of their structure and habit. In this work we report the distinctive features of diffraction patterns that can cause difficulties in the identification of the atomic structure of particles with defect structures containing twins and antiphase boundaries. We describe SEM techniques of particle morphology determination based on the use of illuminating electron beams with different convergent angles and demonstrate obstacles inherent to these techniques.

Приведено описание экспериментальной установки для демонстрации брэгговской дифракции света на 2D−фотонной структуре (двухмерном фотонном кристалле). Рассмотрены условия формирования оптической лауэграммы при отражении света от поверхности фотонного кристалла. Описана методика определения периода решетки фотонного кристалла по его оптической лауэграмме. Получены данные о значении периода решетки фотонного кристалла сгексагональной плотноупакованной структурой.

Instrumented indentation is a very promising technique for studying structural phase transitions in crystalline materials such as silicon.In the present work silicon samples with different crystallographic orientations and doping rates were investigated using indentation with a pyramid indentor of Berkovich type. For studying the electrical properties the indentor was made of semiconductor boron−doped single crystalline diamond. For verification of structural transitions in silicon Raman spectroscopy technique was applied.Electrical current through the contact area under the indentor was measured simultaneously with recording the mechanical response of the material during the indentation process. It is shown that variation in current value gives additional information about the conditions of contact between the indentor and the sample surface. The influence of variations in resistivity and contact area on the measured electrical current value is discussed.

The influence of isothermal annealing on the optical pa-rameters (transmission and diffused reflection spectra,) of La3Ga5.5Ta0.5O14 (langatate, LGT) crystals was studied. The experiment required using the polar cut {101 –0} samples made from crystals grown in athmospheres of argon (Ar), argon with oxygen (Ar + 0,5 % O2) and (Ar +2  % O2). The samples were annealed in vacuum and in air at temperatures from 500 to 1000 oC. Additional investigations were conducted using methods of optical microscopy, atomic force microcopy and diffused reflection spectroscopy. 

Holographic interferometry allows visualizing SAW on the entire specimen surface simultaneously and measuring wave characteristics directly. A special method of SAW characteristics measurements by digital holographic interferometry was developed. The use of a picosecond laser allowed registering high frequency SAW two−exposure interferograms, and optical magnification of the CCD input image was used to increase spatial resolution.As a result we reach a sensitivity and resolution of visu-alization and SAW characteristics measurements that significantly exceeded the commonly known limitations of standard holographic methods. 

The process of silicon nanocluster formation during annealing of single SiO layers and multilayer SiO2—SiO—SiO2 structures or after Si deposition on silicon dioxide substrate was studied. A kinetic Monte Carlo model of silicon nanocluster formation taking into account silicon monoxide formation and dissociation was suggested. Not only temperature and annealing time but also SiO layer thickness determined the nanocluster sizes when SiO2—SiO—SiO2 structures were annealed. Simulation demonstrated that silicon monoxide forming in the Si—SiO2 system at high temperatures plays an important role in the process of nanocluster formation. Silicon monoxide also accounts for some specific features of 3D silicon islands formation during silicon deposition on silicon dioxide surface.

The paper presents computational experiments performed for the dynamic model of the Frank−Read dislocation source. The model is based on numerical solution of parabolic type partial differential equations. The number of forming dislocation loops has been plotted as a function of source base value and applied force magnitude. Dislocation loop velocity graphs during the development of sources with different bases and different stresses have been obtained. Characteristic forms taken by the dislocation loop source are shown for each velocity graph.

Direct measurements of complex inorganic compound crystallization showed an increase in the crystallization heat during melt activation by low−frequency vibrations. Phase equilibrium analysis of semiconductor systems using the quaziideal solution model showed that the observed crystallization heat increase could be a result of cluster destruction in the melt.

The paper presents results of the development of ultraviolet light−emitting diodes based on GaN/AlGaN heterostructures grown on AlN substrates by chloride−hydride vapor phase epitaxy. The peak wavelengths are in the range of 360—365 nm with a spectral width of 10—13 nm; the output optical power of LED dies is 50 mW at 350 mA.

Results of XPS and AES investigation of por−Si/SnOxnanocomposite samples after different modes of heat treatment have been presented. We show that thermaltreatment increases the penetration depth of tin and the stoichiometric coefficient x of the SnOx compound. However, annealing at 600 °C leads to a strong oxidation of the porous matrix and eventual blockage of the tin diffusion channels. Optimization of the heat treatment modes allows one to obtain nanocomposite layers with a sufficient thickness of the por−Si/SnOx nanocomposite for use in gas microsensors.

Рассмотрены сравнительные характеристики полупроводниковых тензорезисторных преобразователей давления на основе структур кремний−на−сапфире. Исследованы два вида конструкции тензорезисторных преобразователей: с одно-слойным упругим элементом на керамическом основании и с двухслойным упругим элементом из сапфира и металла. Показано, что однослойные тензорезисторные преобразователи обладают лучшими характеристиками, чем двухслойные, но они имеют ограниченное применение по диапазонам измеряемого давления.

Памяти л. С. Смирнова (1932—2011 гг.)