Modeling of In0.17Ga0.83N/InxGa1-xN/AlyGa1-yN light emitting diode structure on ScAlMgO4 (0001) substrate for high intensity red emission

An In0.17Ga0.83N/InxGa1-xN/AlyGa1-yN light emitting diode (LED) structure on ScAlMgO4 (0001) substrate is modeled for high intensity red emission. The high indium composition (In > 15%) inside the c-plane polar quantum well (QW) for longer wavelength emission degrades the structural and optical properties of LEDs because of induced strain energy and quantum confinement Stark effect. To compensate these effects, it has been demonstrated by simulation that an AlyGa1-yN cap layer of 2 nm thick and Al composition of 17% deposited onto QW of 3 nm thick and In composition of 35% will allow to have less defect density and higher intensity red emission at 663 nm than that of In0.17Ga0.83N/InxGa1-xN LEDs grown on ScAlMgO4 (0001) substrate. This LED structure has perfect in-plane equilibrium lattice parameter (a(eq) = 3.249 angstrom) and higher logarithmic oscillator strength (Gamma = -0.93) values.