Electronic Band Transitions in γ-Ge3N4

Abstract

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Elastic moduli and refractive index of γ-Ge 3 N 4

“…Figure 4 also shows the wavelength-dependent absorption coefficient of γ-Ge 3 N 4 , κ(λ), which predicts transparency of γ-Ge 3 N 4 at λ > 360 nm corresponding to the photon energy h • ν = 3.44 eV. The latter agrees well with the spectroscopically measured band gap of γ-Ge 3 N 4 of E g = 3.65 (5) eV, confirmed experimentally to be direct [4].…”

“…Paul McMillan participated in this work as a member of the ASU team and continued to study this and other phases of Ge 3 N 4 when he moved to University College London. Today, we know that γ-Ge 3 N 4 is a multi-functional material exhibiting a wide and direct electronic band gap of E g = 3.65 (5) eV combined with a large exciton binding energy, D e , between 170 and 300 meV [4,5], high elastic moduli (tables 1 and 2) and hardness. It is thermodynamically stable at pressures above 10 GPa but recoverable at ambient conditions [2,3,8] and persists heating to approximately 700°C [16].…”

Positron Annihilation Lifetime Spectroscopy Insight on Free Volume Conversion of Nanostructured MgAl2O4 Ceramics

“…Results obtained by PALS can serve as a research background for the development of independent methods of diagnosing nanosized free volumes in ceramic materials, including neutron and heavy-ion irradiated MgAl 2 O 4 spinels [53][54][55], Si 3 N 4 [56], Ge 3 N 4 [57], and AlN [58][59][60] (which are especially promising as diagnostic materials for EUROfusion applications) and also facilitate understanding of porosity, development, and transformation of pores in electrochemical and other devices for energy conversion [61][62][63][64][65][66][67][68].…”

Evolution of Free Volumes in Polycrystalline BaGa2O4 Ceramics Doped with Eu3+ Ions

“…Results obtained by PAL spectroscopy can serve as a research base for the development of independent complementary methods for studying nanosized free volumes in ceramic materials, including neutron and heavy ion irradiated MgAl 2 O 4 spinels [22,27,48], Si 3 N 4 [49], Ge 3 N 4 [50] and AlN [51][52][53], which are especially promising as diagnostic materials for nuclear applications. Other interesting and very important areas are the understanding of porosity, its development and transformation in electrochemical and other devices for energy conversion [54][55][56][57][58][59][60][61][62][63][64].…”