The present disclosure relates to a semiconductor nanostructure. The semiconductor nanostructure includes a substrate and at least one ridge. The substrate includes a first crystal plane and a second crystal plane perpendicular to the first crystal plane. The at least one ridge extends from the first crystal plane along a crystallographic orientation of the second crystal plane. A width of cross section at a position of half the height of the at least one ridge is less than 17 nm. The semiconductor nanostructure is a patterned structure which can lead to generate a quantum confinement effect, such that the impurity scattering phenomenon is reduced.