A hybrid functional calculation of Tm3+ defects in germanium (Ge)

作者：Igumbor E^*; Meyer W E^*

来源：Materials Science in Semiconductor Processing, 2016, 43: 129-133.

DOI：10.1016/j.mssp.2015.12.015

• Defects
• Formation energy
• Charge state

In this work, we present ab-initio calculation results for the Tm3+ interstitial (Tm-i(3+)), vacancy-interstitial complex (V-Ge-Tm-i(3+)) and substitutional (Tm-Ge(3+)) defects in germanium (Ge) as determined by the density functional theory (DFT) using the Heyd, Scuseria, and Ernzerhof (HSE06) hybrid functional. We calculated the formation energies and the charge state transition levels of different configurations. Our results show that the Tm3+ interstitial exists in the hexagonal configuration with low formation energy. The formation energies for V-Ge - Tm-i(3+) and Tm-Ge(3+) were as low as 0.84 eV. The most energetically favourable defects were the V-Ge Tm-i(3+) in the axial configuration and the Tm-Ge(3+). The Tm-Ge(3+) and V-Ge - Tm-i(3+) introduced a single acceptor epsilon(0/ - 1) charge state transition level that was positioned deep in the middle of the band gap. The majority of the levels induced by the defects under investigation, were either shallow donor or acceptor level lying close to the band gap edges.

• 出版日期2016-3-1