Excitation properties of the divacancy in 4H-SiC

Article

关键词: COHERENT CONTROL;    CASCADE CAPTURE;    SILICON-CARBIDE;    DEFECT;    IDENTIFICATION;    ELECTRONS;    VANADIUM;    SPINS;   

DOI  :  10.1103/PhysRevB.98.195202

来源: SCIE

【 摘 要 】

We investigate the quenching of the photoluminescence (PL) from the divacancy defect in 4H-SiC consisting of a nearest-neighbor silicon and carbon vacancies. The quenching occurs only when the PL is excited below certain photon energies (thresholds), which differ for the four different inequivalent divacancy configurations in 4H-SiC. An accurate theoretical ab initio calculation for the charge-transfer levels of the divacancy shows very good agreement between the position of the (0/-) level with respect to the conduction band for each divacancy configuration and the corresponding experimentally observed threshold, allowing us to associate the PL decay with conversion of the divacancy from neutral to negative charge state due to capture of electrons photoionized from other defects (traps) by the excitation. Electron paramagnetic resonance measurements are conducted in the dark and under excitation similar to that used in the PL experiments and shed light on the possible origin of traps in the different samples. A simple model built on this concept agrees well with the experimentally observed decay curves.

【 授权许可】

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