Laser Ultrasound Methods for Investigation of Thermal Properties of Semiconductors Plate with Modified Surface Layer

In the article the results of analyze of laser ultrasound generation in inhomogeneous semiconductors plate is presented. The case of strong absorption of electromagnetic fields is considered. It is shown that in this case submicron surface layer thermal properties influence on thermal distribution evolution. The case of thin infinite plate considered. Peculiarities of excitation and propagation of elastic waves in such media regarding gives the possibility to obtain dispersive equation for laser ultrasound wave-vectors. It is shown that such processes in 1D case can be described. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3515

Investigation of Heat Transfer in Nanocomposite Structures “PS-liquid” Using Photoacoustic Method

The thermal properties of porous silicon and composite «PS-liquid» system have been investigated in this paper. Using the photoacoustic method the values of thermal conductivity of porous silicon and composite systems with liquid have been obtained. It is shown that the value of thermal conductivity «PS-liquid» substantially exceeds the value determined by the model of «parallel structures». The increase of thermal conductivity is due to the improvement of thermal contacts among the crystallites when introducing liquid into the pores. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3511

Examination of Thermally Induced Deformations of Composite System “Porous Silicon – Liquid”

In the paper results of analyze of the pressures that appeared in composite system “porous silicon – liquid” under its heating is presented. The value of thermally induced pressures of liquid in the pores from photoacoustic measurement was estimate. The temperature dependence of pressures that occurred by interaction forces between solid matrixes and liquids was experimentally measurement. The values of these two pressures where compared. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3517

Tin-induced crystallization of amorphous silicon assisted by a pulsed laser irradiation

The process of tin-induced crystallization of amorphous silicon under the influence of different types of laser irradiation was investigated using the method of Raman scattering by thin-film Si-Sn-Si structures. The dependences of the size and concentration of Si nanocrystals on the power of laser radiation was experimentally evaluated and analyzed. As sources of excitation pulse laser radiation with the pulses duration equal to 20 ns and 150 s and wavelengths equal to 535 and 1070 nm was used. The possibility of efficient tin-induced transformation of silicon from amorphous phase to crystalline one in the 200-nm thick layers of a-Si under the action of laser pulses with duration equal to 20 ns was shown. The spatial and temporal distributions of laser induced temperature rise was calculated to interpret experimental results