Effects of O[sub 2] Partial Pressure and Ga Atmosphere on the Luminescence of Native Defects in β–Ga[sub 2]O[sub 3] Phosphor

Abstract

β–normalGa2normalO3 , a native defect luminescent material with blue emission, was fabricated by annealing β–normalGa2normalO3 powders under various O2 partial pressures or in Ga metal atmosphere. Annealing under low O2 partial pressure favors the photoluminescence (PL), which indicates that VO× should be one of the luminescence centers in this phosphor. Annealing in Ga metal atmosphere reduced the PL intensity, which indirectly suggests that VGa× or defect cluster (VGa,VO)× might be another luminescent center. Electron paramagnetic resonance (EPR) measurements verified the existence of single ionized oxygen vacancy (VnormalObold∙) . An EPR signal with g=4.0468 and four hyperfine lines was observed, which is considered to be related to Ga2+ and the hyperfine interaction parameter is 112G . Furthermore, the correlations between PL intensity and the densities of VO∙ as well as Ga2+ were studied. At present, although we can not clarify whether Ga2+ exists as Gaibold∙bold∙ or GaGa′ , VO× , and Ga2+ may act as donors, whereas VGa× or (VGa,VO)× may act as accepters for the luminescence.

Light-emitting Ga-oxide nanocrystals in glass: a new paradigm for low-cost and robust UV-to-visible solar-blind converters and UV emitters

“…3 -centered at 460 nm and extended in a broad range of the visible region -matches in fact the spectral features of the dominant luminescence observed in all lightemitting Ga-oxide materials and attributed to radiative V $ O related to DAP recombination of band-to-band excitations. [10][11][12][13][14] Consistently with this attribution, the blue PLE prole in Fig. 3b ranges from the absorption tail (at about 280 nm) to the high energy limit of the present experiment (at the onset of the vacuum UV region), as expected from band-to-band excited radiative recombination.…”

Diffusion-driven and size-dependent phase changes of gallium oxide nanocrystals in a glassy host

“…3,47 Additional distinct spectral contributions in the green and UV regions are sometimes observed and can be respectively ascribed to electron-hole recombination between oxygen and gallium vacancies and to exciton-like decay mediated by sub-band gap levels. [51][52][53][54] Looking at Fig. 10, we can notice two important features.…”

Mechanisms of Mono‐Vacancy and Oxygen Permeability in Y2SiO5 Orthosilicate Studied by First‐Principles Calculations

“…In recent years, Y 2 SiO 5 has attracted considerable attention owing to its important technological applications, as structural/functional ceramics, including promising candidate of solid state lasers, damage tolerant ceramics, and thermal/environmental barrier coating (TBC/EBC) materials . Because of various difficulties in synthesizing dense, phase‐pure and bulk Y 2 SiO 5 , the significance of this compound as a structural‐functional ceramic was ignored for many years.…”

“…Furthermore, a comprehensive understanding of the mechanism of point defects will promote activities to optimize the properties of rare earth (Ce 3+ , Yb 3+ etc.) activated Y 2 SiO 5 for solid laser applications …”