Ternary silicon germanium nitrides: A class of tunable band gap materials

Abstract

Ternary silicon germanium nitrides with compositions of both Si 1−x Ge x N and (Si 1−x Ge x ) 3 N 4 are predicted to have a band gap that decreases as the germanium:silicon ratio increases. The band gap is indirect for the silicon-rich compounds but becomes direct as the germanium content increases, due to greater mixing of s and p states in the conduction band. This effect of band gap tunability has recently been reported for (Si 1−x Ge x ) 3 N 4 in the spinel structure [Boyko et al., Phys. Rev. B 81, 155207 (2010)]. Our results suggest that this is a more general effect and that ternary group-14 nitrides should form a class of semiconducting materials for which the band gap can be tuned by controlling the composition.

GaP‐ZnS Solid Solutions: Semiconductors for Efficient Visible Light Absorption and Emission

“…Solid solutions provide an effective means of modifying the properties of semiconductors and, in principle, therefore band gaps can be continuously tuned to the desired width for specific applications 3. For example, this can allow band gaps to be reduced to increase photocatalytic efficiency under visible light,4 as has been achieved5, 6 with NaTaO 3 ‐LaCoO 3 and In 1 − x Ni x TaO 4 .…”

Electronic Band Transitions in γ-Ge3N4

“…As any high-pressure non-conducting material, γ-Ge 3 N 4 exhibits high elastic moduli and hardness, [4]; it is also thermally (meta)stable at atmospheric pressure to ~700 ºC [5]. More important is that, soon after their discovery, the group 14 spinel nitrides have been predicted to possesses direct band gaps (E g ) spanning the visible wavelength range and extending in the near-IR and UV ranges of light, from 0.6 eV to 5.0 eV [6][7][8][9][10]. In particular, E g of γ-Ge 3 N 4 was predicted to be between 2.07 eV and 3.6 eV depending on the applied calculation approach (LDA, GGA, GW etc.).…”

Doped GeSe materials for selector applications

“…Hence, another type of defect, probably Ge dangling bonds could be responsible for the OTS switching With the addition of N, the amorphous network which previously consisted of weakly 2-fold co-ordinated chalcogen atoms now has the increased 3-fold co-ordination of N increasing cross linking in the network [12]. N is incorporated into the matrix and forms bonds with Ge [13]. The high Ge-N bond energy partially arises from the huge electronegativity difference between Ge and N which also leads a partial ionic character to the bond.…”