The effect of doping on the hardness of silicon carbide single crystal and its first principles calculations

The hardness values of 4H-SiC silicon with different nitrogen and vanadium doping concentrations is measured by nanoinderter. It is found that the hardness value is positively correlated with the nitrogen doping concentration ranges from 3.50×10
¹⁷
to 8.02×10
¹⁸
cm
^-3
, and high vanadium doping concentration will reduce the hardness value of the silicon carbide. Base on the first principles, the elastic constants of Vasp software are simulated and calculated, and the bulk modulus and shear modulus of non-doped, nitrogen-doped and vanadium-doped 4H-SiC are estimated by Voigt-Reuss-Hill. The calculation results show that the shear modulus of vanadium-doped silicon carbide and nitrogen-doped silicon carbide are lower than that of non-doped silicon carbide.