Halogen $n$-type doping of chalcopyrite semiconductors

We theoretically identify the chemical thermodynamic boundary conditions that will produce $n$-type $CuInSe2$ via halogen doping. Remarkably, we find that due to the low formation energies of the intrinsic defects, $VCu$ and $InCu$ in $CuInSe2$⁠, the growth conditions that maximize the halogen donor incorporation do not yield $n$-type conductivity, whereas the conditions that maximize the concentration of the intrinsic donor $InCu$ do yield $n$-type conductivity. Under the latter conditions, however, the contribution of the halogen donors to the net donor concentration stays significantly below that of $InCu$⁠.