Electrical properties of GaN/poly(3-hexylthiophene) interfaces

摘要

Interfaces between wide-bandgap semiconductors and polymeric electronic materials are model systems for geometrically more complicated interfaces formed in nanostructured composite electronic, photonic, and photovoltaic devices. The wide-bandgap semiconductor GaN is readily available with well-defined electronic and structural properties, including reproducible control of doping and conductivity type, and can ideally serve as the inorganic side of the model system. Electron transport through a GaN/poly(3-hexylthiophene) (P3HT) semiconductor heterojunction depends on the conductivity type of the GaN and on the doping level in the polymer. The total contact resistance of a planar P3HT film with GaN contacts in a symmetric p-GaN/P3HT/p-GaN structure is consistent with the contribution of reversed-biased junction at one of the GaN/P3HT interfaces. An n-GaN/P3HT-GaN structure has a lower total resistance than the p-GaN structure, possibly arising from band-to-band tunneling at the interface. Doping the P3HT layer with iodine greatly reduced the contact resistance for interfaces with both conductivity types of GaN.