Group 13 element nitride crystal layer, self-supporting substrate, and functional element

A group 13 nitride crystal layer comprising a group 13 nitride crystal selected from gallium nitride, aluminum nitride, indium nitride or the mixed crystals thereof, said group 13 nitride crystal layer comprising an upper surface and bottom surface,

• wherein said group 13 nitride crystal layer comprises high-luminance layers and low-luminance layers, each high-luminance layer being a layer that has a brightness higher side when observed by cathode luminescence and each low-luminance layer being a layer that has a brightness lower side when observed by cathode luminescence, the high-luminance layers and low-luminance layers being present alternately and wherein each said low-luminance layer has a thickness of between 3 times and 10 times of a thickness of each said high-luminance layer, wherein each said high-luminance layer comprises an n-type dopant or a p-type dopant and each said low-luminance layer comprises an n-type dopant or a p-type dopant in a lesser amount with respect to the high-luminance layers.