Thermoelectrics

Apr 21, 2020
Silicon-based thermoelectrics

In this project, we developed methods to enhance the thermoelectric performance of silicon-based energy harvesters. We demonstrated how various nanofabrication methods reduce the thermal conductivity of thin films but preserve the electrical conductivity, thus increasing the overall efficiency.

Particularly, arrays of holes can reduce the material thermal conductivity several times. Alternatively, nanopillars of the surface can also reduce the thermal conductivity of underlying membrane. Finally, we proposed a cheap and simple method to reduce the thermal conductivity by covering the surface with an atomic layer of aluminum. Based on this method, we fabricated a planar thermoelectric devices shown in the figure above.

The project currently continues in Nomura lab.

In progress

Related

Publications

Planar-type SiGe thermoelectric generator with double cavity structure

We design and fabricate a planar-type thermoelectric generator with a double cavity structure.
Soita Koike, Ryoto Yanagisawa, Laurent Jalabert, Roman Anufriev, Masashi Kurosawa, Takao Mori, Masahiro Nomura
Applied Physics Letters 124, 123902 (2024).
Project Link

Coherent and incoherent impacts of nanopillars on the thermal conductivity in silicon nanomembranes

Here, we fabricate nanopillars on suspended silicon membranes using damageless neutral-beam etching and investigate the impact of nanopillars on the thermal conductivity of the membranes in the 4–300 K range.
Xin Huang, Daisuke Ohori, Ryoto Yanagisawa, Roman Anufriev, Seiji Samukawa, Masahiro Nomura
ACS Applied Materials & Interfaces 12, 25478 (2020).
Project Project Link

Thermal conductivity reduction in a silicon thin film with nanocones

We propose a cost-effective, large-area, and maskless nanofabrication method that creates external nanocones on the silicon surface while preserving its interior. Our experiments show that these nanocones reduce the thermal conductivity of thin silicon membranes by more than 40%.
Xin Huang, Sergei Gluchko, Roman Anufriev, Sebastian Volz, Masahiro Nomura
ACS Applied Materials & Interfaces 11, 34394 (2019).
Project Project Link

Thermoelectric enhancement of silicon membranes by ultrathin amorphous films

We propose a simple, low-cost, and large-area method to increase the thermoelectric figure of merit (ZT) in silicon membranes by the deposition of an ultrathin aluminum layer.
Anthony George, Ryoto Yanagisawa, Roman Anufriev, Jinghan He, Naoko Yoshie, Naohito Tsujii, Quansheng Guo, Takao Mori, Sebastian Volz, Masahiro Nomura
ACS Applied Materials and Interfaces 11, 12027 (2019).
Project Link

Aluminium nanopillars reduce thermal conductivity of silicon nanobeams

We experimentally investigate heat conduction in suspended silicon nanobeams with periodic arrays of aluminium nanopillars.
Roman Anufriev, Ryoto Yanagisawa, Masahiro Nomura
Nanoscale 9, 15083 (2017).
Project Project Link

Patent: 熱電変換材料およびその製造方法

Masahiro Nomura, Roman Anufriev, Ryoto Yanagisawa, Anthony George
出願番号: 特願 2017-154070 (2017).
Project

Reduction of thermal conductivity by surface scattering of phonons in periodic silicon nanostructures

We investigate the impact of various phonon-scattering mechanisms on the in-plane thermal conductivity of suspended silicon thin films with two-dimensional periodic arrays of holes, ie, phononic crystal (PnC) nanostructures.
Roman Anufriev, Jeremie Maire, Masahiro Nomura
Physical Review B 93, 045411 (2016).
Project Project Link