Exciton States Confined in Strained GaN/Al_xGa_(1-x)N Quantum Dots

Concerning the domino effect of the built-in electric field and the three-dimension confinement,exciton states with hydrogenic-like impurity confined in GaN/AlxGa1-xN quantum dots(QDs) are studied by means of a variational approach within the framework of effective-mass approximation.The results show that when there is hydrogenic-like impurity in the center of QDs,the exciton ground-state energy and the photoluminescence energy are reduced,and the exciton binding energy and the stability of exciton state are increased.When the impurity position is on the upper interphase of QDs,the exciton ground-state energy is lowest,the exciton binding energy the highest and the stability of exciton state the strongest.As the impurity moves to lower interphase of QDs,the ground-state energy and photoluminescence energy increase,and the binding energy reduces.