UV emitters based on an AlGaN p–n junction in the form of graded-index separate confinement heterostructure

Al x Ga 1− x N-based UV emitters in the form of a graded-index separate confinement heterostructure were grown on 6H-SiC. The devices consist of 100 nm Al x Ga 1− x N compositionally graded from x = 0.3 to 0 and x = 0 to 0.3 in two sides. Owing to polarization doping from naturally occurring or intentionally incorporated dopants, the two sides are of the doped p- and n-types, giving rise to a p–n junction. The doping level was calculated to be 10 18 cm −3 for the p- and n-sides. It was found experimentally that this doping level requires the intentional incorporation of Mg and Si, and those devices show better rectification and stronger electroluminescence emission.