Regensburg 2016 – wissenschaftliches Programm
HL 36.23: Poster
Dienstag, 8. März 2016, 15:00–19:00, Poster A
Density functional study of structural, electronic and optical properties of point defects in 2D transition metal dichalcogenides — •Soumyajyoti Haldar1, Hakkim Vovusha1, Manoj Yadav2, Olle Eriksson1, and Biplab Sanyal1 — 1Div. of Materials Theory, Dept. of Physics & Astronomy, Uppsala University, Sweden — 2Nepal Academy of Science and Technology, Nepal
Using density functional theory, we have studied structural, electronic and magnetic properties of various point defects in 2D transition metal dichalcogenides MX2, (M = Mo, W; X = S, Se, Te). Our results shows that the X interstitial defect has the lowest formation energy (∼ 1 eV) for all the systems under the X rich condition whereas for M rich condition, X vacancy has the lowest formation energy except for MTe2 systems. At experimental growth temperatures (1000 - 1200 K), these defects have high equilibrium defect concentrations. In general, the defect states appears in the band gap, which can affect electronic and optical properties of the pure system. Calculation of optical properties show that the optical transitions occurs at ∼ 1.0 eV due to defect states. Our results are expected to guide the experimental nanoengineering of defects to achieve suitable properties related to band gap modifications and characterization of defect fingerprints via optical absorption measurements.