Correlated electron-hole transitions in wurtzite GaN quantum dots:the effects of strain and hydrostatic pressure

Within the effective-mass and finite-height potential barrier approximation,a theoretical study of the effects of strain and hydrostatic pressure on the exciton emission wavelength and electron-hole recombination rate in wurtzite cylindrical GaN/Al_xGa_1-xN quantum dots（QDs） is performed using a variational approach.Numerical results show that the emission wavelength with strain effect is higher than that without strain effect when the QD height is large（> 3.8 nm）,but the status is opposite when the QD height is small（< 3.8 nm）.The height of GaN QDs must be less than 5.5 nm for an efficient electron-hole recombination process due to the strain effect.The emission wavelength decreases linearly and the electron-hole recombination rate increases almost linearly with applied hydrostatic pressure.The hydrostatic pressure has a remarkable influence on the emission wavelength for large QDs,and has a significant influence on the electron-hole recombination rate for small QDs.Furthermore,the present numerical outcomes are in qualitative agreement with previous experimental findings under zero pressure.