Physico-Chemical nanomaterials science

Thermal dispergation of vacuum condensates of Pb-In alloy 
on a molybdenum substrate
Petrushenko S.I., Dukarov S.V., Nevgasimov O.O., Lyalka A.O., Sukhov V.N.
School of Physics V. N. Karazin Kharkiv National University.
4 Svobody Sq., Kharkiv, Ukraine.
E-mail: petrushenkokhnu@gmail.com

As of today, functional nano-arrays are a perspective object of modern technologies. Of particular interest are arrays of disparate metal particles, which are used as biosensors, photocatalytic generators, and light-generating devices, find their application in spintronics and sensor technology. Thermal dispergation of vacuum condensates is a very perspective method for creating functional nano-arrays. This work is devoted to the study of thermal dispergation of Pb-In alloy films on a molybdenum substrate.
The samples for the research were obtained by the method of the consequential condensation in a vacuum of 10-6 mm Hg. Fusible metals were deposited by thermal evaporation from molybdenum boats. Molybdenum was deposited with the help of e-beam evaporation deposition. The mass thickness of each of the layers (and, consequently, the components concentration) was determined by the quartz resonator method. In each experimental cycle, the samples of two types were obtained: one of them, after the condensation, was subjected to short-term heating, which provided the melting of the fusible components, and the second one remained at the room temperature. After the thermal exposure termination, the samples were removed from the vacuum chamber and were examined with the SEM methods.
It was established that, after melting, the samples consist of isolated spherical islands. The size distribution of particles which generated in the result of melting has got the normal nature. The values of the most probable radius and full width at half maximum of the distribution are determined by the thickness of the condensate, but in a wide range of concentrations do not depend on the fusible layer composition. The coverage of the substrate with a film occurs to be significantly lower than in the case of single-component films of the same thickness, which are located on the non-wettable substrate. This indicates that the molybdenum sublayer, used in the work, leads to the condensate structure formation, with which a high value of excess energy is associated with, stimulating the island structure formation.