This study considered the design of an efficient, high brightness polar InGaN/GaN light emitting diode (LED) structure with AlGaN capping layer for green light emission. The deposition of high In (>15%) composition within InGaN quantum well (QW) has limitations when providing intense green light. To design an effective model for a highly efficient InGaN green LEDs, this study considered the compositions of indium and aluminum for In_xGa_{1 - x}N QW and Al_yGa_{1 - y}N cap layers, along with different layer thicknesses of well, barrier and cap. These structural properties significantly affect different properties. For example, these properties affect electric fields of layers, polarization, overall elastic stress energy and lattice parameter of the structure, emission wavelength, and intensity of the emitted light. Three models with different composition and layer thicknesses are simulated and analyzed to obtain green light with in-plane equilibrium lattice parameter close to GaN (3.189 × 10^-10) with the highest oscillator strength values. A structure model is obtained with an oscillator strength value of 1.18×10^-1 and least in-plane equilibrium lattice constant of 3.218 × 10^-10. This emitter can emit at a wavelength of 540 nm, which is the expected design for the fabrication of highly efficient, bright green LEDs.