On the photoinduced heterostructure in a vanadium dioxide film

A non-thermal photoinduced semiconductor-metal phase transition occurring over a time $\Delta t<1$ ps in a vanadium dioxide film on an aluminum substrate is theoretically investigated. It is shown that under the action of a short laser pulse in the VO$_2$ film a structure of metal and semiconductor layers parallel to the substrate is formed. The dependence of the layer thickness on the energy density $W$ of the laser pulse is obtained. A diagram is constructed that determines the number of layers depending on the energy density $W$ of the laser pulse and the thickness $a$ of the film. A comparison with experimental data is made.