We report on the strong in uence of carbon doping on 1/f noise in fully epitaxial Fe/MgO(100) 12 ML/Fe magnetic tunnel junctions in comparison with undoped junctions with a large density of barrier defects. Carbon in uences the relaxation of defects, the reconstruction of the interface and the symmetry transformation of interface resonance states, which are suggested to contribute to the strong...

Graphene-oxide (GO) flakes have been deposited to bridge the gap between two epitaxial-graphene electrodes to produce all-graphene devices. Electrical measurements indicate the presence of Schottky barriers at the graphene/graphene-oxide junctions, as a consequence of the band gap in GO. The barrier height is found to be about 0.7 eV, and is reduced after annealing at 180 degrees C, implying th...

We report an optical study of charge transport in graphene. Diffusion of hot carriers in epitaxial graphene and reduced graphene-oxide samples are studied using an ultrafast pump-probe technique with a high spatial resolution. Spatiotemporal dynamics of hot carriers after a pointlike excitation are monitored. Carrier-diffusion coefficients of 11 000 and 5500 cm2 s−1 are measured in epitaxial gr...

We have studied the photoluminescence properties of as-grown GaAs12xNx epitaxial layers grown on GaAs containing 0.6%, 1.77%, and 2.8% nitrogen. We found laser emission from thick (d .200 nm! GaAs0.972N0.028 layers exhibiting the characteristic lasing properties of random lasers. This is unusual because random lasers have so far only been associated with highly disordered or random media. We be...

Magnetotransport properties have been investigated for epitaxial thin films of B20-type MnSi grown on Si(111) substrates. Lorentz transmission electron microscopy images clearly point to the robust formation of Skyrmions over a wide temperature-magnetic field region. New features distinct from those reported previously for MnSi are observed for epitaxial films: a shorter (nearly half) period of...

The electronic properties of epitaxial semiconductors are strongly modified by the inclusion of semi-metallic nanoparticles grown in the semiconductor. For example, epitaxial semi-metallic nanoparticles can donate carriers, pin Fermi levels, shorten electron–hole recombination times, enhance electron tunneling and increase scattering of phonons in semiconductor host layers. There are dozens of ...

UNLABELLED We outline a metal-free fabrication route of in-plane Ge nanowires on Ge(001) substrates. By positively exploiting the polishing-induced defects of standard-quality commercial Ge(001) wafers, micrometer-length wires are grown by physical vapor deposition in ultra-high-vacuum environment. The shape of the wires can be tailored by the epitaxial strain induced by subsequent Si depositio...

A new MOS gate-controlled power switch with a very low onresistance is described. The fabrication process is similar to that of an n-channel power MOSFET but employs an n--epitaxial layer grown on a p+ substrate. In operation, the epitaxial region is conductivity modulated (by excess holes and electrons) thereby eliminating a major component of the on-resistance. For example, on-resistance valu...

We report the epitaxial growth of thin films of a small organic molecule (pentacene) on polymer substrates with controllable photoalignment over a wide range. The pentacene molecular plane exhibited a distinct orientational change from parallel to perpendicular relative to the polymer chain with increasing substrate polymer alignment. Each orientation consists of twinlike domains. Such characte...