Vacuum power switches

摘要

A vacuum power switch comprising an anode (16), a cathode (12) having an array (20) of aligned carbon nanotubes extending towards the anode (16), and a current switching grid (14) between the cathode (12) and the anode (16). The array (20) of aligned carbon nanotubes may be produced by chemical vapour deposition from a carbon containing gas on to a substrate bearing islands of catalytic metal. <IMAGE>