Thermodynamic Formation Properties of Point Defects in Germanium Crystal

JP Luo and CY Zhou and QH Li and LJ Liu, MATERIALS, 15, 4026 (2022).

DOI: 10.3390/ma15114026

Point defects are crucial in determining the quality of germanium crystals. A quantitative understanding of the thermodynamic formation properties of the point defects is necessary for the subsequent control of the defect formation during crystal growth. Here, molecular dynamics simulations were employed to investigate the formation energies, total formation free energies and formation entropies of the point defects in a germanium crystal. As far as we know, this is the first time that the total formation free energies of point defects in a germanium crystal have been reported in the literature. We found that the formation energies increased slightly with temperature. The formation free energies decreased significantly with an increase in temperature due to the increase in entropy. The estimated total formation free energies at the melting temperature are similar to 1.3 eV for self-interstitial and similar to 0.75 eV for vacancy, corresponding to a formation entropy of similar to 15 k(B) for both types of point defects.

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