Papers by Keyword: Intrinsic Defect

Abstract: In a combined theoretical and experimental work, we have investigated the common DI photoluminescence in 6H-SiC material. We present an atomistic model which is able to explain the annealing behavior, i. e. the correlation with the silicon vacancy, the local vibrational modes and the excitonic-like character observed.

Abstract: Midgap levels in 4H-SiC epilayers have been investigated by DLTS. The EH6/7 center (Ec-1.55 eV) is the dominant deep level as observed in DLTS spectra from n-type epilayers. The activation energy of EH6/7 center is unchanged regardless of applied electric fields, indicating that the charge state of EH6/7 center may be neutral after electron emission (acceptor-like). A DLTS spectrum for a p-type epilayer in the temperature range from 90 to 830 K is dominated by two peaks, D center and a deep trap at 1.49 eV from the valence band edge. Minority carrier traps have been also investigated by DLTS using pn diodes. Two minority carrier traps with activation energies of 1.0 eV and 1.43 eV have been detected.

Abstract: Ag and Cu diffused into CdTe exhibit unusual shapes of their concentration profiles, especially if the diffusion was performed under Cd vapor pressure. The shapes of the concentration profiles at low concentrations of Ag or Cu are well described by a model based on the interaction with intrinsic defects. In that model the characteristic features of the profiles can be independently reproduced by appropriate parameters. It turns out that the resulting profiles are determined by the diffusion of interstitial Cd atoms and reflect the actual distribution of the intrinsic defects in the crystal, i.e. the deviation from stoichiometry.