Optical emission spectroscopy of microscopic gas discharges using a high-pressure scanning tunneling microscope

A high-pressure scanning tunneling microscope (STM) unit was used to produc e electrical discharges on a mesoscopic scale. Piezoelectric positioning el ements allow to adjust the electrode gap with the precision needed. Optical emission spectroscopy was performed in high-pressure environments of heliu m and argon in a range of 5-20 bar. Spectra were recorded at different gas pressures and discharge currents. The increase of gas pressure changed line intensities and caused broadening of spectral lines of helium and argon. I ncreasing the discharge current yielded a higher intensity of the emitted l ight. The use of different electrode materials had no significant influence on the spectra. Electrical gas discharges on the microscopic scale can be used not only as a lithographic tool, but also as a compact light sourer of high luminance with emission of well-defined line spectra. (C) 2000 Americ an Vacuum Society. [S0734-211X(00)01402-5].