Stabilization and behavior of current in a semiconductor gas discharge system

In a semiconductor gas discharge system (SGDS), processes affecting and providing the maintenance of stabilization of a cold-discharge plasma distribution are experimentally investigated in the broad range of discharge gap (45-525 um) in argon plasma with photosensitive semiconductor cathode GaAs:Cr. Quantitative results point out that semiconductor cathode having a spatial distribution resistance feeding the discharge with secondary electron emission process is responsible for government of stabilization of discharge plasma in the broad range of pressure.discharge gap (<47.25 Torr.cm) through all cross section of discharge. For this range, it was observed that the filamentary current distribution is stopped by semiconductor cathode with instantaneous responses. The stability behavior of discharge current was obtained from current-voltage and -time characteristics during the increasing cathode-potential fall of discharge. The magnitude of secondary electrons emitted from surface resulting in interactions with semiconductor cathode of ion and photon plasma species is investigated for the qualitative effects of cold semiconductor cathode current. Measurements and calculations including Townsend coefficients approach were performed for obtainment the magnitudes of secondary electron emitted from cathode surface and the number of ionized collision in gas discharge space. For the first time, the influence of various semiconductor cathodes (GaAs, InP and Si) based on secondary electrons on gas discharge is studied in various gas environments (argon, air, helium, neon and nitrogen). High electric fields occuring in discharge gap give the important contributions in the increasing of number of secondary electrons and ionized collision. It is observed that ion and photon-induced secondary electrons obtained from semiconductor surface reach towards high values in the onset of discharge at the enhanced and reduced values of electric field/number density of gas, respectively. Loss of discharge stabilization was investigated when the increasing cathode-potential fall based on the onset of space-charge effect in gas volume gradually develops. In particular, during the cathode electron flow and ionized collision processes in plasma in the effect of high electric fields establishing in near cathode, current oscillations including N-shaped negative differential resistance formations originating from near cathode were obtained at the low values of current. Hovewer, the discharge current fluctuations and wide hysteresis loops occur with further development of collision processes in plasma volume at atmospheric or atmospheric near-discharge regimes during the development of cathode-potential fall. We hope that the results obtained from SGDS will become important for microplasma systems in evaluation and development of discharge stabilization.