Stable high electron emission from LiNbO3single crystal

A sample of LiNbO₃ single crystal Z-cut slice is stimulated by a high negative voltage submicrosecond pulse to obtain the emission. When the pulse voltage exceeds a threshold, which is 800V in the experiment, we observe a stable high electron emission from the sample´s surface. The threshold is irrelevant to the driving frequency and the anode voltage. Below the threshold the electron emission density increases with the anode voltage, above the threshold the electron emission density varies very little with the anode voltage. The electron emission density reached a peak value of 50A/cm, when the driving pulse V_p-p is 900V. The emission current is not synchronized with the driving signal. When the frequency of the driving voltage is 10 kHz, the frequency of the emission current is only 1 Hz. The frequency of the emission current further decreases, as the driving frequency decreases.