Dense plasma formation on the surface of a ferroelectric induced by a driving pulse with a fast fall time

Experimental results are presented of dense plasma formation on the surface of a BaTi-based ferroelectric sample during the fall time of a driving pulse. A negative or positive driving pulse (less than or equal to14 kV), with a slow rise time (similar to450 ns) and a fast fall time (40-200 ns), was applied to the rear electrode of the ferroelectric. It was found by different electrical, optical, and spectroscopic diagnostics that this method allows one to form a plasma with a larger density (similar to3 x 10(13) cm(-3)) as compared with that formed by a driving pulse with a fast rise time (less than or equal to4 x 10(12) cm(-3)). It was shown that the shorter the fall time of the driving pulse the more intense plasma formation occurs. The most uniform and dense plasma formation occurs with a positive driving pulse. In addition, it was found that the shorter the fall time of the positive driving pulse the larger are the current amplitude, the energy, and the divergence of the emitted electrons. The obtained results are discussed in terms of the surface plasma formation and the compensation process of the polarization surface charge of the ferroelectric sample. (C) 2003 American Institute of Physics.