367. Tb-doped β-(AlxGa1-x)2O3 epitaxial films on c-sapphire substrates fabricated via a spin-coat…

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Iva Milisavljevic, et al, J. Alloys Comp. 928, 167208 (2022)
https://doi.org/10.1016/j.jallcom.2022.167208

(1) The emission bands of Tb-doped β-(AlxGa1-x)2O3 captured in the 300-500 nm wavelength range (UV, blue, and green) resulted from intrinsic defects in the recombination processes in the host material, whereas the emissions in the 500-800 nm range could be assigned to radiative emissions from the Tb dopant.
(2) Rare-earth doping has been explored in the design of multicolor-emitting phosphors and displays (e.g., thin-film electroluminescent displays and field emission displays) that are capable of withstanding high electric fields.
(3) The optical bandgap energy (Eg) was estimated from the difference between the onset of inelastic losses (Eloss) and the position of the core-level O 1s XPS peak (EO 1s), using the following equation: Eg = Eloss-EO 1s.
(4) The highly-oriented growth of all the samples in the (-201) crystallographic family direction suggests that all three films established an epitaxial relationship with the c-sapphire substrates.
(5) Because Al3+ ions have smaller ionic radii (0.54 Å) than Ga3+ ions (0.62 Å), increasing the concentration of Al3+ ions in the Al2O3-Ga2O3 binary solid solution causes the lattice to shrink.
(6) Al in a β-(AlxGa1-x)2O3 crystal lattice can occupy Ga(I) and Ga(II) sites, albeit the preference toward octahedral Ga(II) sites for all compositions with x < 71%.