No abstract

No abstract

The effect of varying the water vapor content in a DC magnetron sputtering process was investigated for zinc oxide film formation. The plasma parameters near the substrate surface were measured using a single Langmuir probe, and the deposited films were characterized using X-ray diffraction, X-ray reflectivity, optical transmittance, and 4-point probe methods. In the region near the substrate surface, the addition of water changes the plasma properties, and the measured plasma parameters showed the changes corresponding to the transition in the film growth mechanism from Zn to ZnO. Depositing at 40% water content resulted to a highly transparent film with a ρ of 1.20 Ω cm. The band gap of films deposited at 40 to 100% settings ranged from 3.36 to 3.34 eV, which matches the expected shallow hydrogen donor doping in ZnO.

One of the methods used to produce ions of metals and metal oxides is through extracting them from a magnetron sputter-type ion source. Metal nanoparticles, such as zinc oxide (ZnO), can be deposited using this method. However, low-energy conditions are required to prevent damage to the substrate. The extraction of ions from a differentially pumped, reactive magnetron sputtering source with a pulsed, conduit-type extraction electrode is investigated, with Zn as the metal target and argon and water vapor as discharge support and reactive gases, respectively. The use of water vapor has been shown to improve the properties of ZnO, through hydrogen doping. Using a quadrupole mass analyzer, the species produced from the ion source were detected and identified. Ar, H2O, H3O, and Zn ions were extracted using the pulsed extraction electrode, and the intensity of the extracted ions were found to be frequency dependent. Extraction of ions were observed starting from-40 V extraction potential using a Faraday cup, and the ion beam current appeared to increase in proportion to the extraction voltage. A mechanism for realizing ion extraction using an alternating extraction potential is proposed.

A low voltage compact ion mobility spectrometer type charged particle analyzer is being investigated to test the performance for diagnostics of ion/electron transport in an atmospheric pressure environment. The 44 mm diameter, 53 mm long device consists of a mesh gated shutter, a 35 mm long drift region, and an end-plate detector. By applying a cyclic positive bias followed by a negative bias to the shutter region, subsequent attraction and expulsion of charged species is observed with the applied voltage less than 100 V. Mesh size dependence of the shutter gated current at the detector shows that across 0, 30, 100, and 200 mesh sizes, the 30 mesh size realized the transport of the most number of ions towards the detector. This mesh size also presents a well-defined currenttime derivative which allows the measurement of ion mobilities in electric fields with the intensity less than 33.3 V/cm. Analysis of peaks observed after the onset of the positive phase shows the presence of O + ions in the swarm with a reported experimental mobility of K 0 = 2.97 cm 2 /Vs.