Group-III nitride structure comprising at least one structure pyramid having a base having at least four sides. The structure pyramid comprises an inner pyramid having a base having at least four sides, which inner pyramid is made of a first group-III nitride. The inner pyramid is coated with an inner first layer made of a second group-III nitride and an outer second layer made of a third group-III nitride, wherein the second group-III nitride has a lower band gap than the first group-III nitride and a lower band gap than the third group-III nitride. The base of the structure pyramid is elongated resulting in an upper ridge creating at least one anisotropic quantum dot.Method for producing a group-III nitride structure comprising providing a substrate; providing a masking film on the substrate, which film comprises at least one elongated aperture; growth of a first group-III nitride on the substrate; deposition of an inner first layer of a second group-III nitride on the first group-III nitride; deposition of an outer second layer of a third group-III nitride on the second group-III nitride, wherein the second group-III nitride has a lower band gap than the first group-III nitride and a lower band gap than the third group-III nitride.