Hall-effect measurements have been performed on a series of highly conductive thin films of Ga-doped ZnO grown by pulsed laser deposition and annealed in a forming-gas atmosphere (5% H2 in Ar). The mobility as a function of thickness d is analyzed by a simple formula involving only ionized-impurity and boundary scattering and having a single fitting parameter, the acceptor/donor concentration ratio K=NA/ND. For samples with d=3–100 nm, Kavg=0.41, giving ND=4.7×1020 and NA=1.9×1020 cm−3. Thicker samples require a two-layer formulation due to inhomogeneous annealing.

A novel growth method (carbon molecular beam epitaxy (CMBE)) has been developed to produce high-quality and large-area epitaxial graphene. This method demonstrates significantly improved controllability of the graphene growth. CMBE with C(60) produces AB stacked graphene, while growth with the graphite filament results in non-Bernal stacked graphene layers with a Dirac-like electronic structure, which is similar to graphene grown by thermal decomposition on SiC (000-1).

We have used the pulsed‐gradient spin‐echo technique to measure self‐diffusion in low‐molecular‐weight polymers in the melt and dissolved in identical polymers of high molecular weight. Specimens used were cis‐polyisoprenes and polydimethylsiloxane. We find that, except for substantial free‐volume corrections, self‐diffusion in unentangled polyisoprene melts scales inversely with molecular weight. The results include sensitive determinations of chain‐end free volume.

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www.iqep.com, Phone: þ01 732 271 5990, Fax: þ01 732 412 9325 In this work we present the epitaxial and device results of AlInN/GaN HEMTs grown on SiC by metalorganic vapor phase epitaxy. High quality AlInN/GaN HEMT structures with sub-10 nm AlInN barrier were grown with very low Ga background level (<1%). The low R sh of 215 V/sq was obtained with an excellent standard deviation of 1.1% across 3 00 wafers. Lehighton RT contactless Hall tests show a high mobility of 1617 cm 2 /V s and sheet charge density of 1.76 Â 10 13 /cm 2 . DC Phys. Status Solidi A 207, No. 6 (2010) 1351 Original Paper 1352 S. Guo et al.: AlInN HEMT grown on SiC by MOVPE for millimeter-wave applications physica s s p status solidi a ß