The Impact of the Amorphous-to-Crystalline Transition on the Upconversion Luminescence in Er 3+ -Doped Ga 2 O 3 Thin Films.

Gallium oxide (Ga₂O₃) is an emerging wide bandgap semiconductor promising a wide range of important applications. However, mass production of high-quality crystalline Ga₂O₃ still suffers from limitations associated with poor reproducibility and low efficiency. Low-temperature-grown amorphous Ga₂O₃ demonstrates comparable performance with its crystalline counterparts. Lanthanide Er³⁺-doped Ga₂O₃ (Ga₂O₃: Er) possesses great potential for developing light-emitting devices, photodetectors, solid-state lasers, and optical waveguides. The host circumstance can exert a crystal field around the lanthanide dopants and strongly influence their photoluminescence properties. Here, we present a systematical study of the impact of amorphous-to-crystalline transition on the upconversion photoluminescence in Ga₂O₃: Er thin films. Through controlling the growth temperature of Ga₂O₃: Er films, the upconversion luminescence of crystalline Ga₂O₃: Er thin film is strongly enhanced over 100 times that of the amorphous Ga₂O₃: Er thin film. Moreover, the variation of photoluminescence reflects the amorphous-to-crystalline transformation of the Ga₂O₃: Er thin films. These results will aid further designs of favorable optoelectronic devices integrated with lanthanide-doped Ga₂O₃ thin films. [ABSTRACT FROM AUTHOR]