The nanorod arrays were fabricated in a custom designed electron-beam deposition system (Torr International, Inc.) [13,33].Fe2O3 nanorods was first deposited onto Si and/or glass substrates
with the incident angle = 86◦, with the substrate rotating azimuthally at 0.5 rev/s. The deposition proceeded until a nominal thickness of 3 m, as determined by a quartz crystal
microbalance (QCM), was achieved. Based on the nanorod separation and height measured using scanning electron microscopy,the vapor incident angle for the TiO2 shell deposition was determined to be = 6.1◦. Further details describing this calculation and the GLAD core–shell deposition method can be found in. Using the same substrate azimuthal rotation rate of
0.5 rev/s, the TiO2 shell was deposited to a nominal thickness of
50 nm. The as-deposited Fe2O3–TiO2 nanorod samples were then
annealed in a quartz tube furnace (Lindberg/Blue M Company) in
open air for 3 h, at different preset temperatures from 350 ◦C to
750 ◦C.
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