(a) Scanning electron microscope (SEM) micrograph of an array of diamond rods fabricated by reactive ion etching (from Ref. 5 with permission). (b) SEM micrograph of nanodiamond cylindrical structures. Cross-sectional view of the diamond cylinder membrane after dissolving the alumina template (from Ref. 8, with permission).
Illustrations of cross sections of DNRs with structures predicted from first principles calculations. The top structures initially contained only (001) and (011) surfaces. The bottom structures contained some (111) surface that partially graphitized during the calculation. (Images courtesy of Dr. A. Barnard, Argonne National Laboratory).
Representative structures from the set of DNR morphologies simulated. The top structures correspond to ⟨001⟩ orientations along the DNR axis; the bottom structures correspond to ⟨011⟩ orientations. Surface orientations for the top structures, left to right: (011), (011) and (001), (001). Surface orientations for the bottom structures, left to right: (011) and (001), (001) and (111), (111).
Atomic enthalpy of formation versus the hydrogen-to-carbon ratio for DNRs of infinite length (via a periodic boundary) corresponding to the different morphologies represented in Fig. 3: solid circles (b), solid squares (c), solid trangles (d), open diamonds (e), open triangles (a), and open squares (f). The dotted line corresponds to a (17,0) nanotube of finite length with the ends hydrogen terminated.
Illustrations of the functionalized CNT and the DNR used in the calculations of thermal conductivity.
Calculated thermal conductivities for DNRs and a CNT as a function of the length of the system (twice the distance between the hot and cold regions in the simulation). (Top panel) DNRs with diameters of 1.1, 1.6, and from top to bottom, respectively. (Bottom panel) The solid diamonds represent data for a (10,10) CNT. The other data are the same as the top panel.
Calculated thermal conductivities as a function of the length of the system for the DNR with a diameter of (top panel) and a (10,10) CNT with a diameter of (bottom panel). (Top panel) Lines from top to bottom correspond to the pristine structure, 1%, 5%, and 10% functionalization, respectively. (Bottom panel) Lines from the top to bottom correspond to the pristine structure, 0.25%, 1%, 5%, and 10% functionalization, respectively.
Thermal conductivities of the functionalized CNT and DNR considered in Figs. 5 and 7 as a function of the percentage of the functionalized surface. The values for the CNT are calculated assuming that the entire interior contributes to the cross-sectional area. Triangles correspond to DNR, squares to CNT, correspondingly.
Summary on diamond one-dimensional structures synthesized up to date. Terms rods, cylinders, and whiskers do not represent particular morphology/geometry and are used according to the authors notation.
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