Density functional theory calculations of helium clustering in mono-, di-, and hexa-vacancy in silicon
L Pizzagalli and ML David and J Deres, PHYSICA STATUS SOLIDI A-APPLICATIONS AND MATERIALS SCIENCE, 214, 1700263 (2017).
Combining classical molecular dynamics and first-principles DFT calculations, we perfom an extensive investigation of low energy configurations for Hen Vm complexes in silicon. The optimal helium fillings are hence determined for V-1, V-2, and V-6 ( figure on the right), and the structures formed by helium atoms arrangements in the vacancy defect are analyzed. For V-1 and V-2, the He atoms structure is mainly controled by the host silicon matrix, whereas a high density helium packing is obtained for V-6. For the latter, we estimate a helium density of about 170 He nm(-3) in the center of the hexa-vacancy at the optimal helium filling. GRAPHICS Relaxed structures obtained from DFT calculations for configurations with the lowest formation energies: ( a) He14V1, (b) He20V2, and ( c) He40V6. (C) 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Return to Publications page