[21a-W323-1~10] 9.4 Thermoelectric conversion

[21a-W323-9] Preparation of Ge-Sb-Te Metastable Thermoelectric Bulks

Tatsuro Omoto¹, 〇Atsuko Kosuga¹ (1.Osaka Pref. Univ.)

Keywords:thermoelectric material,metastable phase

Ge₂Sb₂Te₅ has two single-crystalline phases: a stable phase with hexagonal structure and a metastable phase with cubic structure. The former was prepared by thermal equilibrium reactions, but the latter was only by non-thermal equilibrium reactions, for example, sputtering.Therefore, previous reports on thermoelectric (TE) properties of the cubic compound were restricted to thin-film samples, where the TE properties were found to vary significantly depending on the thickness of the samples. The TE properties of bulk samples have remained unknown. Recently there is a prediction that Ge₂Sb₂Te₅ can be a potential material for low temperature TE application. Inspired by this study, we try to prepare metastable cubic phase as a bulk form and clarify its transport properties below room temperature.