Ti, Al and N adatom adsorption and diffusion on rocksalt cubic AlN (001) and (011) surfaces: Ab initio calculations

C. Mastail, M. David, F. Nita, A. Michel, G. Abadias

Research output: Contribution to journalArticle

Abstract

We use ab initio calculations to determine the preferred nucleation sites and migration pathways of Ti, Al and N adatoms on cubic NaCl-structure (B1) AlN surfaces, primary inputs towards a further thin film growth modelling of the TiAlN alloy system. The potential energy landscape is mapped out for both metallic species and nitrogen adatoms for two different AlN surface orientations, (001) and (110), using density functional theory. For all species, the adsorption energies on AlN(011) surface are larger than on AlN(001) surface. Ti and Al adatom adsorption energy landscapes determined at 0 K by ab initio show similar features, with stable binding sites being located in, or near, epitaxial surface positions, with Ti showing a stronger binding compared to Al. In direct contrast, N adatoms (N ad) adsorb preferentially close to N surface atoms (N surf), thus forming strong N 2-molecule-like bonds on both AlN(001) and (011). Similar to N 2 desorption mechanisms reported for other cubic transition metal nitride surfaces, in the present work we investigate N ad/N surf desorption on AlN(011) using a drag calculation method. We show that this process leaves a N surf vacancy accompanied with a spontaneous surface reconstruction, highlighting faceting formation during growth.

Original languageEnglish
Pages (from-to)354-364
Number of pages11
JournalApplied Surface Science
Volume423
DOIs
Publication statusPublished - 30 Nov 2017
Externally publishedYes

    Fingerprint

Keywords

  • Adatom adsorption
  • DFT calculations
  • Diffusion pathways
  • TiAlN thin film growth

Cite this