Use of laser for study of allocation of vacancies in nanocrystallic films of organic matters

Abstract

The presence of defects in a structure (vacancies causing a diffusion, etc.) can affect quality of a material used in nanotechnology. To study this problem the examination of a nanocrystal film of organic matter by a method of Raman effect has been used. This method picked, as spectrums of the lattice oscillations are rather sensitive to structural change of a crystal. In the capacity of a subject of inquiry the molecular crystal paradibromobenzene which are a good model for the picked object. It is shown the sondage usage by the focused laser beam of films of organic crystals and Raman effect method of light allocation of vacancies in a film. It is found that at diminution ofthickness of a film the number of vacancies will increase up to particular quantity, and their allocation on a film surface in investigated samples is not uniform. The changes of physical properties because of a dimensional change of crystal grains for the structures built from organic molecules, apparently, is observed at their greater size, than for the structures built from atoms.Organic crystals find the increasing application in molecular electronics (at making chips, and in devices of storage). Thus, it is used nanotechnology. Nanostructure properties differ from properties of crystals of greater size. Change of physical properties because of a dimensional change of crystal grains for the structures built from organic molecules, apparently, should be observed at their greater size, than for the structures built from atoms. Thus, the number of defects per unit volume with diminution of the sizes will increase. Besides, surface effect is incremented by physical properties of crystal grains.The presence of defects in a structure (vacancies causing a diffusion, etc.) can affect quality of a used material. For example, the molecule with the changed parameters can migrate and change noted information. It is necessary to know how defects place in the obtained structure (it is even or is not even). Therefore, the increasing value is gained with methods of a non-destructive quality control used is model also examination of the obtained structure nanocrystal a material. As [1] mobility of atoms is scored in-process and, apparently, molecules will increase in nanocrystal substances by 5-6 orders in comparison with routine polycrystals.To study this problem, the examination of a nanocrystal film of organic matter by a method of Raman effect has been lead. This method picked, as spectrums of the lattice oscillations are rather sensitive to structural change of a crystal. In the capacity of a subject of inquiry the molecular crystal paradibromobenzene which are good model object picked. Paradibromobenzene it was studied by various methods. It crystallizes in space group P2, /a with two molecules in a unit cell [2]. It has been prepared three samples. Firstly, the monocrystal paradibromobenzene was brought up. Secondly, the monocrystal film on a glass substrate by thickness -5 m on a method given in-process [3] was brought up. After that, the film wa...