>Oxygen Resistance Investigation of Graphene-Oxide-Semiconductor Planar-Type Electron Sources for Low Earth Orbit Applications

A graphene-oxide-semiconductor (GOS) planar-type electron source is coated with a hexagonal boron nitride (h-BN) film to improve its oxidation resistance. The h-BN film is selected as a coating material owing to its high oxidation resistance and electron transmissivity. To evaluate oxygen resistance, the electron emission density versus applied gate voltage is measured before and after an atomic oxygen (AO) exposure for 4 minutes using an oxygen plasma asher. As a result, the device covered by h-BN emits electrons even after the AO exposure, indicating that the graphene electrode under the h-BN remains.