Features of the band structure of (CuInSe$_2$)$_{1-x}$(MeSe)$_x$ alloys (Me = Mn,Fe)

Experimental data on the concentration dependence of the band gap $E_g (x)$ are acquired and the band structure of (CuInSe$_2$)$_{1-x}$(MeSe)$_x$ alloys (Me = Mn, Fe) is calculated. An increase in $E_g$ upon the sub-stitution of In atoms with Fe or Mn atoms and its decrease upon the substitution of Cu atoms with Fe atoms is established.