Exciton states and interband optical transitions in wurtzite InGaN/GaN quantum dot nanowire heterostructures: Effects of hydrostatic pressure

Considering the hydrostatic pressure, the strong built-in electric field as well as the three-dimensional confinements of the electrons and holes, we solve the confined exciton states and investigate the interband optical transitions in wurtzite InxGa1−xN/GaN strained quantum dot (QD) nanowire heterostructures (NWHETs) using a variational method under the effective mass approximation and the simplified coherent potential approximation. In our calculations, the effective masses of the electron and hole, dielectric constants, phonon frequencies, energy gaps, radius and height of QDs and piezoelectic polarizations are taken into account as a function of hydrostatic pressure. Our results show that the hydrostatic pressure has a significant influence on the exciton states and interband optical transitions. The exciton binding energy increases with the hydrostatic pressure. The emission wavelength has a blue-shift (red-shift) if the hydrostatic pressure (QD height) increases. For the small radius or the large height QDs, the hydrostatic pressure dependence of the exciton binding energy is more obvious. The hydrostatic pressure can effectively enhance the exciton oscillator strength and improve the light emission efficiency of InxGa1−xN/GaN QD NWHETs. The physical reason has been analyzed in depth.

► The pressure has a significant influence on exciton states and optical transitions.
► The exciton binding energy increases with the hydrostatic pressure.
► Wavelength has a blue-shift (red-shift) if pressure (quantum dot height) increases.
► The pressure can enhance the exciton oscillator strength of InGaN/GaN nanowires.
► The pressure can improve the light emission efficiency of InGaN/GaN nanowires.