Breakdown Phenomenon and Electrical Process in a Microplasma System with InP Electrode

The electrical characteristics of InP have been investigated experimentally and its electron density and electrical potential evaluated theoretically using the finite element method in a two-dimensional (2D) medium. Higher ionization rates were achieved at 39.99 kPa and 450 V, and the maximum electron density in the cell was found to lie around ~ 8.64 × 1023 m−3. The main motivation for the use of InP electrodes is the promising optoelectronic characteristics of this material. The plasma currents and gas discharge emissions were recorded simultaneously for an InP electrode under air or He medium. The breakdown voltage was investigated under various operating conditions including He and air plasma. Use of air resulted in a better minimum breakdown point compared with He; that is, the minimum voltage was reached at lower pressure, viz. p = 3.73 kPa for air versus p = 25.99 kPa for He. The system was found to depend on the pressure of the cell, with a transition occurring from the Townsend to glow mode. Self-sustained discharge contributed to the current–voltage characteristics and light emission over a wide pressure range between 1.99 kPa and 101.325 kPa for various interelectrode gaps. It has been shown that the intensity of the plasma is higher in air than He, being 10 a.u. for air versus about 5 a.u. for He under the same conditions.