The research of ultrathin vanadium nitride (VN) films as a promising candidate for superconducting single-photon detectors (SSPD) is presented. The electron diffusivity measurements are performed for such devices. Devices that were fabricated out from 9.9 nm films had diffusivity coefficient of 0.41 cm2 /s and from 5.4 nm – 0.54 cm2 /s. Obtained values are similar to other typical SSPD materials. The diffusivity that increases along with decreasing of the film thickness is expected to allow fabrication of the devices with improved characteristics. Fabricated VN SSPDs showed prominent single-photon response in the range 0.9-1.55 µm
Shock waves actions upon materials perspective for using in future thermonuclear fusion reactors are investigated experimentally and by means of numerical modelling. The shocks are generated by powerful streams of plasma and fast ions in Dense Plasma Focus devices as well as by irradiation with a laser operating in a Q-spoiled mode. Power flux densities of these streams on the targets’ surfaces are in the range 1014 – 1016 W/m2. They are used for tests of the above materials, and their influences are compared for a number of substances. It is shown that in the above-mentioned identical conditions Plasma Foci generate shock waves with amplitudes of approximately two times higher than that for the laser case. Fronts of the shocks are formed here faster than at the laser irradiation. A simple analytical formula for calculations of the amplitudes of shock waves in radiation material science experiments provided with Dense Plasma Focus devices are advanced.
We researched the relation between deposition and ultra-thin VN films parameters. To conduct the experimental study we varied substrate temperature, Ar and N2 partial pressures and deposition rate. The study allowed us to obtain the films with close to the bulk values transition temperatures and implement such samples in order to fabricate superconducting single-photon detectors