Anharmonic vibrations of the dicarbon antisite defect in 4H-SiC

Yan, F.*; Devaty, R. P.*; Choyke, W. J.*; Gali, A.*; Kimoto, Tsunenobu*; Oshima, Takeshi; Pensl, G.*

Dicarbon antisite defects were introduced into 4H Silicon Carbide (SiC) by either electron irradiation or ion implantation (H or He) and subsequent annealing between 700 and 1700 C for 30 min in Ar. As a result of low temperature photoluminescence at 2 K, the no-phonon lines from the dicarbon antisite defect center were detected with their phonon replicas. The stretch frequencies of the defect with up to the fifth harmonic were also observed. The Morse potential model accounts for the anharmonicity quite well and gives a very good prediction of the vibration energies up to the fifth harmonic at an error within 1%. The observed anharmonicity can be explained in terms of the model of a dicarbon antisite defect along with its four nearest neighboring carbon atoms using first principles calculations.