Ar+ ion irradiation and annealing E effects on the structure and electric properties of Pbsub(0.7))=Snsub(0.3 Te films on KCl

The effect of Ar+ ion irradiation and subsequent vacuum annealing on the structure and electric properties of epithaxial films of Pbsub(0.7)Snsub(0.3)Te on KCl were investigated. Film thickness constituted 1000 A. The films were solid, had hole conductivity with a charge carrier concentration of apppoximately 2x1018 cm-3 and 150-300 cm2xB-1xs-1 mobility at room temperature. 40 KeV Ar+ ions were used for irradiation at a dose of 3x1015 cm-2. After the measurements of the conductivity and Hall emf a part of the film was carried to a small net for the review by the JEM-6 electron microscope. The film was annealed on a substrate in vacuum at 360 deg C during 20-40 min and then the conductivity was measured again with the subsequent review of the film by the electron microscope. It is established that thin epithaxial films of Pbsub(1-x)Snsub(x)Te solid solutions grown by means of condensation in vacuum are very inhomogeneous in their structure and beside electrically active point defects contain the aggregates of point defects forming in the films local deformations and are the centers of charge carrier scattering. On irradiation argon ions interact both with atoms in lattice points and the whole set of growth defects. This results in the appearance of new and regrouping of old defects and their aggregates. Radiation defects are unstable and disappear after annealing in vacuum at 360 deg C during 30 min, at that, local stresses existing in the films both before and after irradiation are eliminated and the structure becomes more ordered