Influence of Au on Ge Crystallization and Its Thermoelectric Properties in a Au-induced Ge Crystallization Technique (original) (raw)

2018, JOURNAL OF ADVANCES IN PHYSICS

Poly-crystalline Ge (pc-Ge) thin films were prepared on a SiO2/Si substrate using Au-induced crystallization (GIC) of amorphous Ge (a-Ge) with an annealing temperature around the eutectic point of Au-Ge alloy system (361ºC) in order to shorten the annealing time. Bilayer thin films of Au (20 nm)/a-Ge (100 nm) were used as a precursor material and annealed at 300, 400, and 500 ºC for 60 min, which successfully leads to the formation of pc-Ge layers. Characterizing the prepared Ge layers, the crystallographic properties indicated that the metal catalyst Au plays a notable role of enhancing both the crystallization and the island formation of Ge layers. It was also shown that the pc-Ge hardly contains Au atoms. Therefore, the Seebeck coefficient was hardly influenced by Au atoms since they do not act as a carrier source. In addition, the thermal conductivity of the pc-Ge film prepared by the GIC method was higher than that formed without Au, which is not due to the Au catalyst itself...