Ab initio investigation of the AlN:Er system

TL;DR

This study uses ab initio methods to analyze the structural and electronic effects of erbium doping in AlN, confirming solid solution formation and metastable site incorporation, with implications for optoelectronic properties.

Contribution

It provides a detailed ab initio analysis of Er incorporation in AlN, including site stability, lattice effects, and band structure modifications, extending to AlNO.

Findings

Er forms a solid solution in AlN up to 12.5% concentration.

Er incorporation induces shallow states in the bandgap.

Lattice constants and bandgaps vary with Er concentration.

Abstract

In the present study an ab initio investigation on the AlN:Er system for concentrations of Er ranging from 0.78 to 12.5 % is presented. The crystallographic localisation of the rare earth atoms in the wurtzite lattice is determined, elucidating previously published experimental deductions, and the existence of a solid solution in the AlN:Er system in this range is confirmed. Er incorporation in the tetrahedral and octahedral insertion sites is shown to be thermodynamically metastable and is found to induce shallow states in the bandgaps. The effect of Er concentration on the lattice constants and bandgaps and bandstructures of the ErxAl1-xN ternary compound is presented. Finally, in accordance with experimental specifications, Er incorporation in the AlNO system is also examined.