InGaN/GaN quantum well exhibits a series of unusual optical properties.However

the physics of quantum well on the micro scale is subjected to large uncertainties.Little is known on the discontinuities of energy band structure and local states on the atomic level in the case of different In atoms distribution in the In

x

Ga

1-x

N layers caused by In compositional fluctuation and phase separation

which intensively alters the optical and electronic pro-perties.Using the efficient and accurate total energy and molecular-dynamics package VASP which is based on the density functional method

we performed the first principles calculations on InGaN/GaN quantum wells.The calcu-lated results exhibit discrete bands around the conduction band minimum and the valence band maximum that vary with the In atom distributions.Moreover

the local states with the discrete bands are likely to appear the quantum confined Stark effect in the InGaN/GaN interface enhanced by the polarization field in the crystal.The control and further understanding of those micro characteristics may lead to the improved performance of InGaN QWs.