Al$_{5+\alpha}$Si$_{5+\delta}$N$_{12}$, a new Nitride compound

TL;DR

This paper reports the synthesis and detailed structural analysis of a new nitride compound, Al$_{5+eta}$Si$_{5+ au}$N$_{12}$, revealing its unique layered structure and proposing a range of possible stoichiometries for its semiconducting properties.

Contribution

The study introduces a novel nitride compound with a unique layered structure and provides detailed experimental and theoretical analysis of its atomic arrangement and stoichiometry.

Findings

Identified a new nitride compound with a layered structure.

Determined the compound's structure using HRSTEM, EDX, and DFT.

Proposed a range of stoichiometries for potential semiconducting applications.

Abstract

We report on the synthesis of new nitride-based compound by using annealing of AlN heteroepitaxial layers under a Si-atmosphere at temperatures between 1350$^\circ$C and 1550$^\circ$C. The structure and stoichiometry of this compound are investigated by high-resolution scanning transmission electron microscopy (HRSTEM), energy dispersive X-Ray (EDX) spectroscopy, and density functional theory (DFT) calculations. The identified structure is a derivative of the parent wurtzite AlN crystal where anion sublattice is fully occupied by N atoms and the cation sublattice is the stacking of 2 different planes along <0001>. The first one exhibits a $\times$3 periodicity along <10-10> with 1/3 of the sites being vacant. The rest of the sites in the cation sublattice are occupied by equal number of Si and Al atoms. Assuming a semiconducting alloy, which is expected to have a wide band gap, a range of stoichiometries is proposed, Al$_{5+\alpha}$Si$_{5+\delta}$N$_{12}$, with $\alpha$ being between 0 and 1/3 and $\delta$ between 0 and 1/4.