n-type conductivity in Si-doped amorphous AlN: an ab initio investigation

Abstract

We report the electronic structure and topology of a heavily Si-doped amorphous aluminium nitride (Al_37.5Si_12.5N₅₀) using ab initio simulations. The amorphous Al_37.5Si_12.5N₅₀ system is found to be structurally similar to pure amorphous aluminium nitride. It has an average coordination number of about 3.9 and exhibits a small amount of Si–Si homopolar bonds. The formation of Si–Al bonds is not very favourable. Electronic structure calculations reveal that the Si doping has a negligible effect on the band gap width but causes delocalization of the valence band tail states and a shift of the Fermi level towards the conduction band. Thus, amorphous Al_37.5Si_12.5N₅₀ alloys show n-type conductivity.

Keywords:

• Ab initio method
• amorphous semiconductors
• density-functional method
• electrical conductivity
• aluminium alloys
• molecular dynamic simulations

Additional information

Funding

This work was supported by the Scientific and Technical Research Council of Turkey (TÜBİTAK) under [grant number 114C100].