Cathodoluminescence Properties of Undoped and Zn-Doped AlxGa1-xN Grown by Metalorganic Vapor Phase Epitaxy

Cathodoluminescence of undoped and Zn-doped Al x Ga1-x N epitaxial layers grown by Metalorganic Vapor Phase Epitaxy (MOVPE) in the composition range of 0≤x≤0.3 has been studied at room temperature. The dominant emission of undoped Al x Ga1-x N grown at 1030°C is a near-band-edge emission (UV band), while that of Zn-doped Al x Ga1-x N grown at 1030°C is a violet-blue one (VB band), and that of Zn-doped Al x Ga1-x N grown at 910°C is a blue-green one (BG band). Each emission band shifts toward a higher-energy side with increasing x. The compositional dependence of the peak energy of the UV band is similar to that of the band gap energy. On the other hand, the compositional dependences of the VB band and BG band are somewhat smaller than that of the band gap energy.