Non-oxide materials (nitrides, chalcogenides, and arsenides)

Abstract

Non-oxide semiconductors are often studied and used for photoelectrochemical solar fuel production. Since the anions and cations of crystals can be selected for non-oxide semiconductor materials, the controllability of the conduction and valence band edge potentials, especially that of the valence band edge, is better than that for oxide semiconductors, which is an interesting characteristic of photoelectrochemical electrodes. Non-oxide semiconductors, especially those made of group VI semiconductor material and the III–V compound semiconductor materials formed of group III and group V elements, are used for semiconductor devices like transistors, light-emitting diodes (LEDs), and laser diodes (LDs) due to their extremely good material qualities and controllable p- and n-type polarities and because structurally different materials can be combined. In addition, since non-oxide materials such as single crystals are put to practical applications, they can also be used as the photochemical materials discussed here. Some non-oxide monolithic materials can split water; thus, it is one of the most applicable materials for photoelectrochemical reactions. Most non-oxide materials are, however, not stable in aqueous acidic and/or basic solutions. It is therefore important to protect these materials from dissolution, especially in photoelectrochemical water-splitting applications. This section mainly discusses the photoelectrochemical properties of non-oxide single crystals.