Electrical and spectroscopic study of DC microdischarges made in alumina
Résumé
Microdischarges are under investigation for some applications such as bright light microsources for MEMS devices. Some other applications may emerge in materials processing. Different microdischarges have been recently designed at the Plasma Application Laboratory of UTDallas. A clean room was necessary for the preparation of the samples. An electrodeposition of gold and nickel was performed on a 650 µm thick square of alumina. Alumina was chosen because of its good properties in terms of hardness and ability to resist to high temperature. After deposition, the sample was drilled on different places by a laser process. Two different diameters were available for the channel: 150 µm and 250 µm. The two electrodes were connected to a DC power supply through a 100 kΩ resistance to avoid arcing. The microdischarge was mounted in a small reactor to control pressure and to operate the plasma in different gases (He, Ar, Air). I-V curves were taken in different gases and for different pressures from 60 mbar to 1.6 bar. Up to 10 mA current was reached at atmospheric pressure in He, which corresponds to an injected power as high as 2 W in the 0.01 mm3 channel. Optical emission spectroscopy as well as electrical characterization were carried out for the different gases and will be presented at the conference.