Explosive crystallization in the course of formation of Se/Ag nanosize film structure

Results of an experimental study of explosive crystallization appearing in the process of formation of a Se/Ag nanosize film structure are presented. It is shown that explosive crystallization appears in a wide range of Se film thicknesses (70–280 nm) and occurs during a narrow time interval (2.00–4.52 s). The cooperative effect of the thermal energy of the phase transformation of Ag$_2$Se and the energy of elastic stress in the amorphous Se film leads to development of an explosive crystallization. It was found that, depending on the relative thicknesses of Se and Ag films, orthorhombic Ag$_2$Se with crystal-lattice constants $a$ = 4.333 $\mathring{\mathrm{A}}$, $b$ = 7.062 $\mathring{\mathrm{A}}$, and $c$ = 7.764 $\mathring{\mathrm{A}}$ and hexagonal Se ($a$ = 4.3552 $\mathring{\mathrm{A}}$ and $c$ = 4.9495 $\mathring{\mathrm{A}}$) are formed in the reaction products upon the explosive crystallization.