Order–disorder transition in wurtzite InxGa1−xN

Order–disorder transition conditions for wurtzite InxGa1−xN are represented. Two types of ordered InxGa1−xN are considered. In the first type, alternating (112̄0) planes of the cation sublattice are mainly occupied by In and Ga, respectively. The second type corresponds to the wurtzite-type structure of α-BeSiN2. The decrease of the strain energy is a cause of the formation of the superstructure in wurtzite InxGa1−xN. The order–disorder transition should be continuous. At 0 °C the range of ordered InxGa1−xN extends from x=0.14 to x=0.96. At higher temperatures the ordered states are also in the vast composition ranges. In0.575Ga0.425N possesses the maximal temperature of the phase transition equal to 1140 °C. The significantly larger ordering in InN-rich alloys in comparison with GaN-rich is a result of the asymmetry of the strain energy.

► Two superstructures of wurtzite InxGa1−xN are described. ► In and Ga atoms are mainly in the alternating (112̄0) planes in the first one. ► Another type corresponds to the wurtzite-type structure of α-BeSiN2. ► The phase transition conditions are investigated.