Secondary electron emission and charging characteristics of ion-irradiated sapphire

• Kinetic characteristics of single crystal sapphire irradiated by keV electrons are studied.
• A change of charging characteristics of sapphire is observed after ion bombardment.
• Secondary electron emission yield is found to depend on the relief on the sapphire surface. The mechanisms are discussed.

Kinetic characteristics of sapphire (α-Al2O3) single crystal irradiated by keV electrons are studied. We compare untreated sapphire with surfaces bombarded with Ar+ ions and/or coated with a thin Al film. The electron emission yield and the charging characteristics for the untreated sapphire surface and for that bombarded by Ar+ ions differ significantly. This difference is less when the sapphire sample is coated with a thin film of Al. We propose an explanation for the observed effects.