Impurity-related binding energy in strained (In,Ga)N asymmetric coupled QWs under strong built-in electric field

• The structure size and its constitution have a great influence on the binding energy.
• The binding energy is the largest at a point corresponding to the maxima of the electron wave-function and a larger value is obtained compared to uncoupled QWs.
• The principle effect of the BEF is to reduce the binding energy.
• The competition effect between the quantum confinement and the BEF is shown.

The shallow-donor ground-state binding energy of wurtzite strained (In,Ga)N asymmetric coupled quantum wells (ACQW) is calculated. Within the effective-mass and the one-band parabolic approximations, the structure size, the composition of well and the barrier, the position of the impurity and the built-in electric field effects are investigated using a variational approach under finite confinement potential. The competition effect between the quantum confinement potential and the BEF is also shown. Our results reveal that the binding energy is the largest at a point corresponding to the maxima of the electron wave-function and a larger value is obtained compared to uncoupled QWs. Moreover, the principle effect of the BEF is to reduce the binding energy. It is established that the binding energy can be easily modulated by modifying the structure size, its constitution and the impurity׳s position.