28 research outputs found
Structural and electronic characterization of (2,3(3)) bar-shaped stacking fault in 4H-SiC epitaxial layers
Crystallographic, electronic, and energetic analyses of the (2, 3_3) [or (2, 3, 3, 3) in the standard Zhadanov notation] bar-shaped stacking fault, observed in as-grown 4H-SiC epitaxial layers, are presented. The defect has been identified by means of spatially resolved microphotoluminescence (ÎŒ-PL) measurements at different emission wavelengths, focusing on the emission peak at 0.3 eV below the conduction band. Low temperature ÎŒ-PL measurements have also been performed. The defect has been identified and characterized using high resolution transmission electron microscopy. Experimental results are correlated and validated by the calculations of the KohnâSham electronic band structure and the defect formation energy
Surface and Image-Potential States on the MgB_2(0001) Surfaces
We present a self-consistent pseudopotential calculation of surface and
image-potential states on for both -terminated () and
-terminated () surfaces. We find a variety of very clear surface and
subsurface states as well as resonance image-potential states n=1,2 on both
surfaces. The surface layer DOS at is increased by 55% at and by
90% at the surface compared to DOS in the corresponding bulk layers.Comment: 3 pages, 6 figure