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In-situ NMR spin-lattice relaxation measurements were performed on several vapor deposited ices. The measurements, which span more than 6 orders of magnitude in relaxation times, show a complex spin-lattice relaxation pattern that is strongly dependent on the growth conditions of the sample. The relaxation patterns change from multi-timescale relaxation for samples grown at temperatures below the amorphous-crystalline transition temperature to single exponential recovery for samples grown above the transition temperature. The slow-relaxation contribution seen in cold-grown samples exhibits a temperature dependence, and becomes even slower after the sample is annealed at 200K. The fast-relaxation contribution seen in these samples, does not seem to change or disappear even when heating to temperatures where the sample is evaporated. The possibility that the fast relaxation component is linked to the microporous structures in amorphous ice samples is further examined using an environmental electron scanning microscope. The images reveal complex meso-scale microporous structures which maintain their morphology up to their desorption temperatures. These findings, support the possibility that water molecules at pore surfaces might be responsible for the fast-relaxation contribution. Furthermore, the results of this study indicate that the pore-collapse dynamics observed in the past in amorphous ices using other experimental techniques, might be effectively inhibited in samples which are grown by relatively fast vapor deposition.
The two-dimensional (2D) semiconductor molybdenum disulfide (MoS2) has attracted widespread attention for its extraordinary electrical, optical, spin and valley related properties. Here, we report on spin polarized tunneling through chemical vapor de
Transistor structures comprising graphene and sub-wavelength metal gratings hold a great promise for plasmon-enhanced terahertz detection. Despite considerable theoretical effort, little experimental evidence for terahertz plasmons in such structures
Nanodiamond crystals containing single color centers have been grown by chemical vapor deposition (CVD). The fluorescence from individual crystallites was directly correlated with crystallite size using a combined atomic force and scanning confocal f
Large-area two-dimensional (2D) materials for technical applications can now be produced by chemical vapor deposition (CVD). Unfortunately, grain boundaries (GBs) are ubiquitously introduced as a result of the coalescence of grains with different cry
Simple vacuum evaporation technique for deposition of dyes on various solid surfaces has been developed. The method is compatible with conventional solvent-free nanofabrication processing enabling fabrication of nanoscale optoelectronic devices. Thin