Crystal orientation effects on the optical properties of wurtzite GaN/AlN quantum dots on semi-polar substrates

The study of the optical properties of epitaxial quantum dots is important in the development of high-performance opto-electronic devices and room-temperature quantum light sources. This study focuses on the effects of crystal orientation on the spontaneous emission peak of wurtzite GaN/AlN quantum dots grown on semi-polar substrates. Theoretical analysis shows that a tenfold increase in the spontaneous emission peak can occur as the crystal orientation changes from θ= 0 ^∘ to θ= 90 ^∘. This significant shift is attributed to the change in the optical dipole matrix elements, which is caused by the change in the screening of the built-in potential of the wurtzite quantum dots with the variation in crystal orientation. The spontaneous emission peak is seen to increase rapidly when the crystal angle exceeds θ= 50 ^∘.