Progress on diamond PIN diode emitters with negative electron affinity for high-voltage d.c. vacuum switches

We have reported on ultra-high-voltage vacuum switches using diamond pin diode-type electron emitters with negative electron affinity. Based on the previous 10-kV demonstration, we present our recent progress on high-current operations at 4 A/cm2 in these vacuum switches. We confirmed a normally-off mode at a high voltage of 7 kV; in addition, we evaluated the capability of this device based on our model.