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Results of capacitance-voltage measurements are reported for metal-oxide-semiconductor capacitors fabricated using the 4H polytype of silicon carbide doped with either nitrogen ͑n͒ or aluminum ͑p͒. Annealing in nitric oxide after a standard oxidation/reoxidation process results in a slight increase in the defect state density in the lower portion of the band gap for p-SiC and a significant decrease in the density of states in the upper half of the gap for n-SiC. Theoretical calculations provide an explanation for these results in terms of N passivating C and C clusters at the oxide-semiconductor interface.

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.

We report the confirmed occurrence of Fowler–Nordheim hole tunneling in p-4H–SiC metal-oxide-semiconductor capacitor structures. The effective mass for holes in the oxide is found to be in the range of 0.35m–0.52m, where m is the free electron mass.

The relationship between nitrogen content and interface trap density (Dit) in SiO2/4H–SiC near the conduction band has been quantitatively determined. Nitridation using NO significantly reduces Dit near the conduction band, but the effect saturates after ≈2.5×1014 cm−2 of nitrogen. These results are consistent with a model of the interface in which defects such as carbon clusters or silicon suboxide states produce traps with energies corresponding to the sizes of the defects. Nitrogen passivation results in the dissolution of the defects, which then lowers the energies of the traps in the band gap.

Nitric oxide postoxidation anneal results in a significant decrease of defect state density (Dit) near the conduction bandedge of n-4H–SiC at the oxide/(112̄0) 4H–SiC interface. Comparison with measurements on the conventional (0001) Si-terminated face shows a similar interface state density following passivation. Medium energy ion scattering provides a quantitative measure of nitrogen incorporation at the SiO2/SiC interface.

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The temperature-dependent electrical characteristics of Schottky rectifiers fabricated with a SiO2 field plate on a freestanding n− gallium nitride (GaN) substrate were reported in the temperature range of 298–473K. The Schottky barrier heights evaluated from forward current-voltage measurement revealed an increase of Schottky barrier height and series resistance but a decrease of ideality factor (n) with increasing temperature. However, the Schottky barrier heights evaluated from capacitance-voltage measurement remained almost the same throughout the temperature range measured. The Richardson constant extrapolated from ln(J0∕T2) vs 1∕T plot was found to be 0.029Acm−2K−2. A modified Richardson plot with ln(J0∕T2) vs 1∕nT showed better linearity, and the corresponding effective Richardson constant was 35Acm−2K−2. The device showed a high reverse breakdown voltage of 560V at room temperature. The negative temperature coefficients were found for reverse breakdown voltage, which is indicative of a defect-assisted breakdown.