Thermochemical processes of laser-matter interaction as a mean for creating quasi-one-dimensional nanomaterials

Abstract

Possibilities and features of thermochemical processes of interaction of powerful laser radiation with matter and optical systems for control of spatial distribution of beam intensity are described. Laser beams possess good focusing capabilities and provide the possibility to perform chemical reactions, including metal oxidation, locally and with high spatial resolution. With the use of laser beams with frequency modulation, a synergistic effect between the laser heat actions and the vibrations induced by the laser pulses is created. Thus, the coefficient of diffusion increases considerably as result of the nonstationary strain-stress state of the material. The synthesis of ZnO/Cu semiconductor-metal nanocomposite on the surface of brass samples is described. As a result of pulse-periodic laser treatment, anisotropic quasi-one-dimensional structures - zinc oxide nanowires - are formed on the material surface, i.e. on the conductive metal substrate. By using free-form diffractive optics to shape the laser beam, it is possible to control the chemical processes on the material surface. The resulting material structures are promising for sensor applications due to the sensitivity of ZnO to various chemical agents, biocompatibility, and the possibility of modifying it by various methods.