Point-defect-induced colossal dielectric behavior in GaAs single crystals

Abstract

We herein reported colossal dielectric constant (CDC) behavior in GaAs single crystals. This behavior appears in the temperature range above room temperature and results from the bulk effect due to polaron relaxation caused by hopping motion of EL2 defects. When temperature rises higher than 420 K, the interfacial contribution due to Maxwell–Wagner relaxation caused by sample/electrode contacts appears. When temperature is higher than 560 K, the CDC behavior is mainly contributed by the interfacial effect. These features are quite different from the CDC behavior found in oxides, and therefore, the CDC behavior in GaAs single crystals is considered as a new type of the CDC family. Our results underscore the role of point-defects in CDC behavior and suggest that defect engineering can be a promising strategy to achieve superior CDC behavior in both oxide and non-oxide materials.