Studies On The Binding Energies Of Impurity States In A Strained Wurtzite GaN/Al_xGa_1-xN Quantum Dot And Electron Wave Functions In The GaN/Al_xGa_1-xN Coupled Quantum Dots

Within the effective-mass approximation, the binding energies of impurity states in a strained wurtzite GaN/AlxGa1-xN quantum dot are investigated and the related electron wave functions along the growth direction (z-direction) in the GaN/AlxGa1-xN coupled quantum dots are studied in the presence of external fields.Firstly, a variational method is adopted to discuss the binding energies of hydrogenic impurity states in a strained wurtzite cylindrical quantum dot by considering the hydrostatic pressure. The results indicate that the binding energies with strain effect are higher than that without strain effect when the quantum dot size is small, but the binding energies with strain effect become lower than that without strain effect as the quantum dot size increases. It is also found that the binding energies increase when the Al content decreases. In addition, the binding energies increase obviously with increasing hydrostatic pressure, and the hydrostatic pressure has a remarkable influence on the binding energy for a small quantum dot.Then, a transfer matrix method is adopted to discuss the related electron wave function along the growth direction (z-direction) in the GaN/AlxGa1-xN coupled quantum dots in the presence of external fields. The results indicate that the change of the related electron wave function along the growth direction (z-direction) is remarkablely infueucedly the size of quantum dots, the middle barrier layer thickness, Al component content and the infensity of an external electric field.