Four-level nonvolatile small-molecule 4F(2) memory cells were developed with a sandwiched device structure consisting of an upper Al electrode, upper small-molecule layer (Alq(3), aluminum tris(8-hydroxyquinoline)), Ni nanocrystals surrounded by NiO tunneling barrier, lower small-molecule layer, and bottom Al electrode. In particular, an in situ O(2)-plasma oxidation process following Ni evaporation was developed to produce uniformly stable 10 nm Ni nanocrystals surrounded by a NiO tunneling barrier embedded in the small-molecule layer. They presented a memory margin (I(on)/I(off) ratio) of approximately 1 x 10(3), a retention time of more than 10(5) s, an endurance of more than 5 x 10(2) erase-and-program cycles, and multilevel cell (MLC) operation, being a terabit nonvolatile memory-cell. A vertically double-stacked 4F(2) multilevel nonvolatile memory cell was also developed, showing a memory margin of approximately 1 x 10(3) in both the top and bottom memory cells and eight-level cell operation.

Lanthanide-organic complexes of the general type Ln[N(SiMe(3))(2)](3) (Ln = La, Sm, Y, Lu) serve as effective precatalysts for the rapid, exoselective, and highly regioselective intramolecular hydroalkoxylation/cyclization of primary and secondary alkynyl alcohols to yield the corresponding exocyclic enol ethers. Conversions are highly selective with products distinctly different from those generally produced by conventional transition metal catalysts, and turnover frequencies as high as 52.8 h(-1) at 25 degrees C are observed. The rates of terminal alkynl alcohol hydroalkoxylation/cyclization are significantly more rapid than those of internal alkynyl alcohols, arguing that steric demands dominate the cyclization transition state. The hydroalkoxylation/cyclization of internal alkynyl alcohols affords excellent E-selectivity. The hydroalkoxylation/cyclization of the SiMe(3)-terminated internal alkynyl alcohols reveals interesting product profiles which include the desired exocyclic ether, a SiMe(3)-eliminated exocyclic ether, and the SiMe(3)-O-functionalized substrate. The rate law for alkynyl alcohol hydroalkoxylation/cyclization is first-order in [catalyst] and zero-order in [alkynyl alcohol], as observed in the intramolecular hydroamination/cyclization of aminoalkenes, aminoalkynes, and aminoallenes. An ROH/ROD kinetic isotope effect of 0.95(0.03) is observed for hydroalkoxylation/cyclization. These mechanistic data implicate turnover-limiting insertion of C-C unsaturation into the Ln-O bond, involving a highly organized transition state, with subsequent, rapid Ln-C protonolysis.

Thin high-quality gallium nitride (GaN) nanowires were synthesized by a catalytic chemical vapor deposition method. The synthesized GaN nanowires with hexagonal single-crystalline structure had thin diameters of 10-50 nm and lengths of tens of micrometers. The thin GaN nanowires revealed UV bands at 3.481 and 3.285 eV in low-temperature PL measurements due to the recombination of donor-bound excitons and donor-acceptor pairs, respectively. The blue shifts of UV bands in the low-temperature PL measurement were observed, indicating quantum confinement effects in the thin GaN nanowires which have smaller diameters than the exciton Bohr radius, 11 nm. For field emission properties of GaN nanowires, the turn-on field of GaN nanowires was 8.5 V/microm and the current density was about 0.2 mA/cm(2) at 17.5 V/microm, which is sufficient for the applications of field emission displays and vacuum microelectronic devices. Moreover, the GaN nanowires indicated stronger emission stability compared with carbon nanotubes.