Pulsed TGS-Based Electron and Ion Emitter

Energy distribution of plasma-assisted electron and ion emission from TGS single crystals

“…The second emission processes are more dominating at lower temperatures and they need higher field magnitude to be developed at temperatures close to the phase transition temperature. It was reported for TGS crystals [5,17] that the electron current emitted into vacuum under switching conditions, can screen the depolarizing field only in the temperature range close to the Curie temperature; the transient negative surface potential on the emitting sample surface is independent on time while the electrons are emitted. At temperatures close to room temperature the increase of this surface potential was observed; it means that the density of emitted charge is not sufficient to screen the depolarizing field discussed above.…”

“…It was reported earlier in [5,17] that under the influence of a drive ac electric field the TGS crystal samples can operate as a source of electrons with energies up to a few tens of eV and even the electron energies can be gained to about 200 eV [22]; under plasma-assisted surface processes the electrons and ions with energies up to a few hundred of eV can be produced on pure and La alanine doped TGS single crystals [17][18][19][20][21].…”

“…The measurements were conducted with the use of a PC and suitable data acquisition board [5,17,19]. Three channels in the A/D card were utilized to control the ac voltage supplied to the sample, exciting current and sawtooth-shaped voltage employed in a planar three-section energy analyzer.…”

“…This problem is widely discussed in review paper given by Rosenman et al [16]. In the case of L-a alanine doped TGS (LATGS) crystals which have shown internal bias exceeding 10 3 V/cm, the electron emission processes were observed during negative as well as positive charging of the emitting sample surface due to switching of the spontaneous electric polarization, and also during normal charging of the dielectric sample [17][18][19]. The LATGS sample studied were excited by a drive 500 Hz ac electric field with amplitude higher than 5 Â 10 3 V/cm.…”

Peculiarity of Low Density Plasma-Assisted Charge Emission Produced at LATGS Crystal Surface

“…In the case of L-α alanine doped TGS (LATGS) single crystals maintained at 315 K, the electron emission processes were generated during negative as well as positive charging of the emitting sample surface due to switching of the spontaneous electric polarization and also during mere charging of the dielectric sample [9][10][11]. Under driving ac (500 Hz) electric field with amplitude not less than 5 × 10 3 − 10 4 V/cm, two quite different energy spectra for electrons were observed, i.e., broad with electron energy up to about 400 eV (for negative switching current) or more focused at about 200 eV when ion emission assists electron emission (for positive switching current or mere charging of the sample); the ions have only broad energy spectra.…”