Texture effect of neodymium doped gallium oxide thin films on their optical properties

Neodymium doped β-Ga2O3 films were elaborated on (1 0 0) silicon and (0 0 0 1) sapphire substrates by the radiofrequency magnetron sputtering method. X-ray diffraction, transmission electron microscopy, spectroscopic ellipsometry and photoluminescence measurements were performed to characterize and compare layers elaborated on the two substrates. Also, the Nd content effects were investigated. Films prepared on sapphire substrates were found to form a close orientation relationship with the substrate (−2 0 1) β-Ga2O3 || (0 0 0 1) sapphire, whatever the Nd content in the matrix. By contrast, the films grown on silicon substrates lose this texture for high Nd concentrations with a concomitant decrease of the Nd ions luminescence.

Research highlights
► The texture of the Ga2O3:Nd3+ films is governed by the (−2 0 1) planes.
► The (−2 0 1) texture appears more pronounced for a Nd content of 2.4 × 1019 at cm−3.
► A degradation of the (−2 0 1) texture with Nd content is observed with a silicon substrate.
► A film grown on a sapphire substrate remains textured even for high Nd concentrations.
► The PL signal of the Nd ions is affected by the loss of the film texture.