講演情報
[16a-WL2_101-2]Substrate and thickness dependent thermoelectric performance of n-type Si-Ge thin films
〇(P)Madhuvathani Saminathan1, Priyanka Sangwan1, Ryogo Ishihara1, Masaharu Matsunami1, Tsunehiro Takeuchi1 (1.Toyota Tech. Inst.)
キーワード：
Thermoelectrics、Thin films
Thermoelectric (TE) technology is regarded as an efficient and environmentally benign energy conversion approach due to its reliability, scalability, and ability to operate over a wide temperature range. Microscale TE power generation has attracted significant attention for microelectronic and optoelectronic applications, where effective thermal management is essential to enhance device performance and operational stability. The efficiency of energy conversion in a TE generator is governed by the constituent materials’ dimensionless figure of merit, ZT = S2σT/k, where S, σ, k and T denote the Seebeck coefficient, electrical conductivity, thermal conductivity, and absolute temperature, respectively. Achieving a high power factor (S2σ) in conjunction with low k remains a key challenge in designing a high performance TE material. Extensive band-structure and phonon-engineering strategies have been applied to high-performance TE materials such as Bi2Te3, PbTe and Ag-Pb-Sb-Te; however, their widespread commercialization is hindered by issues related to material cost, toxicity, and long-term sustainability. Si-Ge-based thin films have emerged as promising alternatives owing to their compatibility with semiconductor technologies, high carrier mobility, and larger S. While bulk Si-Ge alloys exhibit poor TE performance at room temperature, controlled modification of electronic structure and microstructural feature in thin films has enabled substantial performance enhancement. In this work, we present a systematic study of the TE transport properties of n-type Si-Ge-P thin films deposited by RF sputtering. σ and S measurements were carried out on films fabricated under identical deposition conditions, with deliberate variation in film thickness and substrate. The study reveals pronounced differences in the transport properties, underscoring the critical influence of film-substrate interactions on the TE behavior of films, which will be discussed in detail in the presentation.