Theoretical evidence for efficient p-type doping of GaN using beryllium

TL;DR

This paper provides theoretical evidence that beryllium can serve as an efficient p-type dopant in GaN, with potential for high doping levels through co-incorporation techniques during growth.

Contribution

It demonstrates that Be is a shallow acceptor in GaN and explores methods to enhance its solubility and incorporation during growth processes.

Findings

Be has a thermal ionization energy of 0.06 eV in GaN.

Be incorporation is limited by Be_3N_2 formation.

H-assisted and Be-O co-incorporation can improve doping levels.

Abstract

Ab initio calculations predict that Be is a shallow acceptor in GaN. Its thermal ionization energy is 0.06 eV in wurtzite GaN; the level is valence resonant in the zincblende phase. Be incorporation is severely limited by the formation of Be_3N_2. We show however that co-incorporation with reactive species can enhance the solubility. H-assisted incorporation should lead to high doping levels in MOCVD growth after post-growth annealing at about 850 K. Be-O co-incorporation produces high Be and O concentrations at MBE growth temperatures.