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Experimental and theoretical characterization of an inductively coupled plasma source J. Appl. Phys. 90, 587 (2001); 10.1063/1.1375009Stabilizing inductively coupled plasma source impedance and plasma uniformity using a Faraday shieldThe electron temperature and ion density produced by a microfabricated plasma generator are characterized in both argon gas and air. The plasma generator sustains a discharge by inductively coupling 450 MHz rf power into a small ͑10 mm diameter͒ vacuum chamber. The inductively coupled plasma source is surface micromachined on a glass wafer by electroplating a planar spiral inductor and two interdigitated capacitors. A plasma can be sustained using gas pressures between 0.1 and 10 Torr and rf powers between 0.3 and 3 W. The ion density increases from 10 10 to 10 11 cm Ϫ3 over this range of power. The electron temperature decreases from 4 to 2 eV as the pressure increases from 0.1 to 1 Torr.

We successfully synthesized well aligned ZnO nanowire (ZnO NW) arrays on Si (100) and indium tin oxide (ITO) glass substrates at the low temperature of 500 °C by a two-stage growth process without metal catalyst. The synthesized ZnO NWs had diameters in the range of 50−100 nm and lengths in the range of 5−8 μm. X-ray diffraction showed that ZnO NW arrays had single-crystal wurtzite structures and grew along the c-axis. Photoluminescence spectra revealed that the ZnO NWs showed a strong UV band at 3.2 eV and a broad green band at 2.3 eV at room temperature. We also observed that the alignment situation and UV band emission of the ZnO NW arrays was enhanced with an increased O2 flow rate in the first stage. In addition, various O2 gas flow rates affected the morphologies of the ZnO nanomaterials. We present a detailed discussion regarding the growth behavior and mechanism of the ZnO NW arrays in this study.

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