Knowledge Bank

Recent research at Ohio State University has identified materials which exhibit p-type and n-type polarity along perpendicular axes, creating a new class of materials described as goniopolar. While nearly all the currently known goniopolar materials are metals, several goniopolar semiconductors have recently been identified. The objective of this investigation was to determine if palladium dichalcogenides, such as PdS2 and PdSe2, are goniopolar semiconductors. This was done by calculating the band structure of each material using density-functional theory, then finding the thermopower along each axis to identify the charger carriers. PdSe2 exhibited goniopolarity at undoped levels in both the x-z and y-z axes, while PdS2 exhibited goniopolarity at undoped levels in the x-z axes only. However, though p-type doping, PdS2 can exhibit goniopolarity in the y-z axes, and PdSe2 can retain goniopolarity for both p-type and n-type doping. The addition of palladium dichalcogenides to the pool of goniopolar semiconductors, and the methods used to identify goniopolarity, has many potential applications in electronic devices.