Influence of In composition on exciton confined in self-formed InxGa1−xN/GaN quantum dots

Based on the effective-mass approximation and variational approach, exciton states confined in self-formed wurtzite InxGa1−xN/GaN quantum dots are investigated theoretically, in which the three-dimensional confinement of electron–hole pair and the strong built-in electric field are considered. The relationship between exciton states and structural parameters of quantum dots with height L and In composition x is studied. Our results show that the maximum of exciton binding energy is obtained at a height of about L=1.4 nm for different In compositions x. The exciton binding energy, emission wavelength and oscillator strength depend sensitively on the height L and In composition x in the InxGa1−xN active layer. The calculated emission wavelength is in good agreement with the experimental measurements for different InxGa1-xN quantum dots.

Research highlights
► The strong built-in electric field is estimated to be in the order of MV/cm.
► The maximum of binding energy is obtained at about L=1.4 nm for different In compositions x.
► The exciton states depend sensitively on structural parameters and In composition x.
► Choosing the suitable structural parameters and In composition x is important.