Thermal Diffusivities of Tris(8-hydroxyquinoline)aluminum and N,N'-Di(1-naphthyl)-N,N'-diphenylbenzidine Thin Films with Sub-Hundred Nanometer Thicknesses

Abstract

The thermal diffusivities of tris(8-hydroxyquinoline)aluminum (Alq3) and N,N'-di(1-naphthyl)-N,N'-diphenylbenzidine (α-NPD) films have been characterized quantitatively using a “rear heating/front detection-type” nanosecond thermoreflectance system. Alq3 or α-NPD films sandwiched by Al films, Al/(Alq3 or α-NPD)/Al three-layered films, were prepared by vacuum evaporation. Al acted as a reflective layer for pulse lasers in the thermoreflectance system. The nominal thicknesses of Alq3 and α-NPD layers varied roughly from 30 to 100 nm. The thermal diffusivities of Alq3 and α-NPD films were found to be (1.4–1.7)×10-7 and 1.4×10-7 m2 s-1, respectively.