We report on the observation of ultraviolet lasing in optically pumped ZnO nanonails synthesized by thermal chemical vapor deposition method. The lasing threshold was found to be 17MWcm−2. Very sharp emission peaks (full width at half maximum of 0.08nm) were observed in the emission spectrum, indicating a high Q factor of the cavity formed by the hexagonally shaped nanonail head. The analysis of the lasing spectra strongly suggests the whispering gallery mode lasing from a hexagonally shaped head of the single ZnO nanonail.

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Specific contact resistances measured at elevated temperatures for Ni ohmic contacts to 6H-SiC were reported. The specific contact resistances were measured with the linear transmission line method at both room temperature and at 500 °C and yielded values <5×10−6 Ω cm2 at both temperatures. The trend shows a decreasing contact resistance at higher temperatures. The annealed metal film is a nickel silicide with substantial mixing of C throughout the silicide layer.

Self-assembled monolayers of thioctic acid (1,2-dithiolane-3-pentanoic acid) on Au surfaces were studied by electrochemical desorption experiments and X-ray photoelectron spectroscopy. The cathodic stripping of thioctic acid monolayers from Au electrodes in 0.5 M KOH electrolyte is characterized by two desorption features. The first, centered at -0.93 V (vs Ag/AgCl), is in good agreement with earlier studies of thioctic acid monolayers on Au. The second peak occurs at about -1.27 V and, to our knowledge, has not previously been reported. Kinetic studies, in which electrochemical desorption curves and XPS spectra were recorded as the total self-assembly time was varied from 1 min to 2 weeks, reveal two distinct adsorption states of thioctic acid on gold surfaces. The first voltammetric wave (-0.93 V) is associated with the desorption of thioctic acid itself, and the second is due to the desorption of oxidized thioctic acid (present as the both the disulfinate and the disulfonate). Finally, oxidized TA was prepared by two synthetic routes and selfassembled monolayers of oxidized TA were allowed to form. Electrochemical desorption experiments showed a single desorption wave at -1.27 V, confirming our assignment.

Methods for studying semiconductor surface chemistry are presented. It is shown that adsorption and desorption kinetic measurements, when combined with Auger spectroscopy, can give useful insights into fundamental elementary surface kinetic processes which are important in understanding the behavior of complex chemical vapor deposition, plasma vapor deposition, or reactive ion etching processes. Techniques for crystal preparation, mounting, temperature control, and reaction kinetic measurements are given using examples from the adsorption and reaction of propylene with Si(100). An illustration of the manipulation of active site availability on Si(100) is described.