Atmospheric-pressure photoelectron emission from H-terminated and amino-terminated diamond (Phys. Status Solidi A 8∕2016)

Among diamond's many unusual properties is the ability to act as a negative electron affinity material. While electron emission from diamond has been heavily studied in vacuum, recent work by Hamers and co-workers has shown that diamond can also act as a solid-state emitter of electron in liquids. In their article on pp. 2069−2074, Hamers and Bandy explore the direct emission of electrons into atmospheric-pressure gases, using argon, air, and SF₆ as model systems. In contrast to the more commonly used hydrogen-terminated diamond, amineterminated diamond provides a fixed positive surface charge that helps to effectively extract electron from the bulk. Electrons emitted into air and into SF₆ can form stable anions (O₂ – and SF₆ –), leading to electron emission currents controlled by the ion mobilities. In contrast, argon does not form a stable anion, so electrons transported through argon gas are transported as free electrons, albeit subject to frequent scattering events. This work provides new insights into the nature of electron emission from diamond and extends its use as a solid-state emitter of electrons in ambient environments.