Calculation of phase separation in wurtzite Ini_1-x-y-zGa _xAl_yB_zN

The miscible region of InGaAlBN quinary system was simulated by using the strictly-regular-solution approximation. The interaction parameter to obtain excess enthalpies caused by mixing was calculated using the delta-lattice- parameter model. The results show that the miscible regions of the InGaAlBN are located near the InN-rich region, near BN, and near the line connecting GaN to AlN. This means that InGaAlBN quinary system makes it possible to design infrared optical devices with InN or In-rich InGaN as an active layer without any strain, which shortens device lifetime. InGaAlBN devices could possibly outperform the InGaAsP devices presently used in optical communications systems.