Location of lanthanide impurity energy levels in the III–V semiconductor AlxGa1−xN (0 ⩽ x ⩽ 1)

Using spectroscopic data on lanthanide ions in AlxGa1−xN (0 ⩽ x ⩽ 1) and recently developed methods, the 4f ground state energy for each divalent and trivalent lanthanide relative to the valence and conduction band is established. The obtained energy level schemes provide a complete description of relevant optical and luminescence properties of lanthanide doped AlxGa1−xN (0 ⩽ x ⩽ 1). Especially, the relation between thermal quenching of Eu3+ or Tb3+ emission and the location of the energy levels is explained. The schemes reveal which trivalent lanthanide ions are able to trap electrons in their 4f-shell and which lanthanide ions are potential hole traps.