Specific features of self-compensation in Er$_x$Sn$_{1-x}$Se solid solutions

The effect of doping and degree of compensation on the conductivity activation energy $\Delta E_i$ in Er$_x$Sn$_{1-x}$Se has been investigated. The carrier concentration decreases at a low doping level in the case of low and moderate compensations. It is found that, beginning with $x\ge$ 0.005 at% Er, carriers in the solid solutions under study change sign, depending on the amount of substituted erbium in the SnSe samples that is in equilibrium with the selenium phase. This phenomenon can be explained in terms of the concepts of the self-compensation of donors in the Sn sublattice.