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A heterogeneous reaction mechanismbased on elementary reactionsteps is proposed for the prediction of pyrolytic carbon depositionin chemical vapor infiltration, involving 72 surface species and 277surface elementary reactions. A “prototype” gas-phasereaction is chosen to match with the corresponding surface reaction,and correction methods for kinetic data are also proposed for threekinds of surface reactions (i.e., surface/gas reactions, unimolecularsurface reactions, surface/surface reactions) in the present work.Simulation results of deposition kinetics and gas-phase compositionsof propane pyrolysis are validated by previously published experimentalresults of Marquaire’s group, with a surface to volume ratiofrom 5 to 175 cm–1and temperature from 1173 to1323 K. The reaction pathways of the heterogeneous surface reactionsand homogeneous gas-phase reactions are studied on the basis of thereaction flow rate analysis. An acceptable agreement indicates thatthe present heterogeneous reaction mechanism is reasonable, and acetylene,ethylene, and benzene are recognized as the main precursors of thepyrolytic carbon deposition at the present processing conditions. [ABSTRACT FROM AUTHOR]

We report on the magnetotransportproperties of chemical vapordeposition grown films of interconnected Bi2Te3nanoplates. Similar to many other topological insulator (TI) materials,these granular Bi2Te3films exhibit a linearmagnetoresistance (LMR) effect which has received much recent attention.Studying samples with different degree of granularity, we find a universalcorrelation between the magnitude of the LMR and the average mobility(⟨μ⟩) of the films over nearly 2 orders of magnitudechange of ⟨μ⟩. The granularity controlled LMReffect here is attributed to the mobility fluctuation induced classicalLMR according to the Parish–Littlewood theory. These findingshave implications to both the fundamental understanding and magnetoresistivedevice applications of TI and small bandgap semiconductor materials. [ABSTRACT FROM AUTHOR]