Effects of dopant concentration on structural and near-infrared luminescence of Nd3+-doped beta-Ga2O3 thin films

We have investigated structural and near-infrared (NIR) luminescence of Nd3+-doped β-Ga2O3 thin films (Nd:Ga2O3) with different Nd3+ doping concentrations. With an increase of Nd3+ content, the crystal lattice of the films expands, while the energy band gap shrinks. Moreover, NIR luminescence is investigated as a function of Nd3+ doping concentration. The measured results are related to the structural change and energy transfer of cross relaxation process ascribed to 4F3/2—4I9/2, 4F3/2—4I11/2, and 4F3/2—4I13/2 of the phosphor films. This work implies that the enhanced NIR luminescence and blue-shift observation are associated with the lattice distortion and the variation in the crystal field of Nd: Ga2O3.