Abstract
In this study, spectroscopic investigations are employed to quantify the Ga distribution over the tetrahedral/octahedral sites and to assimilate the luminescence properties in the barely reported γ-Ga2.67O4 : Sm nanoparticles.
Highlights
Gallium-oxide (Ga2O3) polymorphs i.e.; a-Ga2O3, b-Ga2O3, gGa2O3, d-Ga2O3 and 3-Ga2O3,1–4 have evoked much attention because of their wide range of applications in optoelectronics, gas sensing, magnetic tunnel junctions, photo-catalysis, biomedical elds, etc.[5,6,7,8,9] Among all the known phases of Ga2O3, g-Ga2O3 is the class of material which possesses a cubic or defective-spinel crystal structure with uneven occupancy of Ga at the tetrahedral and octahedral sites.[2,3,4] The strong correlation between the metal atom site occupancy and its structural/ optical/electronic properties make g-Ga2O3 an attractive material for investigating the fundamental connections between the crystal/electronic structure and unexplored applications.Most of the reports on g-Ga2O3 have considered the cubic unit cell of this compound;[8,10,11,12] a defective spinelTheoretical studies have shown that the band structure of Ga2O3, near the Fermi level, is formed by the O 2p and Ga 4s states
Quantitative determination of the cation distribution is performed by applying Ga K-edge X-ray absorption near edge structure (XANES) data analysis, which is further substantiated by an EXAFS data simulation, and conveys a Ga-O4 tetrahedra/Ga-O6 octahedra ratio (Ga(t)/Ga(o)) of $0.9, $1.4, $1.5 and $1.6 for the b-Ga2O3, gGa2.67O4, g-Ga2.67O4 : 5Sm and g-Ga2.67O4 : 10Sm samples, respectively, which signify the Sm doping induced deformation of Ga-O6 octahedra via the formation of oxygen defects
Synthesis with DI water and liquid ammonia solution could only grow GaOOH kinds of phases which further transformed into a-Ga2O3, g-Ga2O3 and b-Ga2O3 phases upon high-temperature annealing.[18,19]
Summary
Gallium-oxide (Ga2O3) polymorphs i.e.; a-Ga2O3, b-Ga2O3, gGa2O3, d-Ga2O3 and 3-Ga2O3,1–4 have evoked much attention because of their wide range of applications in optoelectronics, gas sensing, magnetic tunnel junctions, photo-catalysis, biomedical elds, etc.[5,6,7,8,9] Among all the known phases of Ga2O3, g-Ga2O3 is the class of material which possesses a cubic or defective-spinel crystal structure with uneven occupancy of Ga at the tetrahedral and octahedral sites.[2,3,4] The strong correlation between the metal atom site occupancy and its structural/ optical/electronic properties make g-Ga2O3 an attractive material for investigating the fundamental connections between the crystal/electronic structure and unexplored applications.Most of the reports on g-Ga2O3 have considered the cubic unit cell of this compound;[8,10,11,12] a defective spinelTheoretical studies have shown that the band structure of Ga2O3, near the Fermi level, is formed by the O 2p and Ga 4s states.
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