Berlin 2024 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 14: Materials for Storage and Conversion of Energy IV

MM 14.4: Vortrag

Montag, 18. März 2024, 17:30–17:45, C 264

Ab-initio study of doping in silicon carbide — •Zahra Rajabzadeh and Lorenz Romaner — Department of Materials Science, Montanuniversität Leoben, Roseggerstraße 12, 8700 Leoben, Austria.

The wide band gap semiconductor SiC is an outstanding material for high-power electronics, e.g. for inverter applications in electric cars.. Although SiC is generally doped with elements such as N or Al, the fundamental properties of these point defects are still not understood.

We use density functional theory (DFT) calculations to investigate the impact of dopants on SiC properties focusing on the most relevant polytypes 3C, 6H, 4H and 2H. Calculations are carried out with the Vienna Ab- initio Simulation Package (VASP). We employ the PBE exchange-correlation functional with and without van der Waals (vdW) corrections as well as the HSE06 hybrid functional. First, we present results where a nitrogen or aluminum atoms are placed inside the crystal structure for different polytypes and the formation energy for different dopants are discussed. Then we will discuss binding energy for (N, Al) co-doping configurations. Furthermore, we explore concentration effects which allow studying the impact of non-stoichiometry on the formation energies. The results for all defects are analyzed also in terms of the electronic structure including band gaps and projected density of electronic states. Finally, we discuss nitrogen solubility to understand how much nitrogen can dissolved in SiC.

Keywords: point defects; density functional theory; SiC polytypes; Formation energy; dopants concentration