Iron diselenide thin films synthesized by soft selenization of iron films

Ferroselite (FeSe2) thin films crystallized in the orthorhombic structure have been obtained by selenization of iron pre-deposited films. The iron films have been deposited by evaporation on soda lime glass. Then these samples have been selenized in vacuum sealed Pyrex tube. The annealing conditions were Ta=773 K for 2 h. The XRD study shows that the crystallites are oriented with their c-axis parallel to the plane of the substrates. As shown by SEM they are rectangularly well shaped. The crystallite thickness is equal to the film thickness. It is shown that there is no oxygen contamination of the bulk of the film, while X-ray photoelectron spectroscopy study shows that the surface and near surface domain is partly contaminated. Typically, the conductivity of FeSe2 films is 3.84 Ω cm−1, the carrier concentration (p) of these p-type films is 4×1018 cm−3 and their carrier mobility is only 6 cm2/Vs−1.