Electronic structures of ternary alloys of group III (Al, Ga, In) and rare earth (Sc, Y, Lu) nitrides were investigated from first principles. The general gradient approximation (GGA) was employed in predictions of structural parameters, whereas electronic properties of the alloys were studied with the modified Becke-Johnson GGA approach. The evolution of structural parameters in the materials reveals a strong tendency to flattening of the wurtzite type atomic layers. The introduction of rare earth (RE) ions into Al- and In-based nitrides leads to narrowing and widening of a band gap, respectively. Al-based materials doped with Y and Lu may also exhibit a strong band gap bowing. The increase of a band gap was obtained for Ga1-xScxN alloys. Relatively small modifications of electronic structure related to a RE ion content are expected in Ga1-xYxN and Ga1-xLuxN systems. The findings presented in this work may encourage further experimental investigations of electronic structures of mixed group III and RE nitride materials because, except for Sc-doped GaN and AlN systems, these novel semiconductors were not obtained up to now.
Keywords: band gap; calculations; nitride semiconductors.