Elevated thermoelectric figure of merit of n-type amorphous silicon by efficient electrical doping process
Journal article, 2018

The currently dominant thermoelectric (TE) materials used in low to medium temperature range contain Tellurium that is rare and mild-toxic. Silicon is earth abundant and environment friendly, but it is characterized by a poor TE efficiency with a low figure of merit, ZT. In this work, we report that ZT of amorphous silicon (a-Si) thin films can be enhanced by 7 orders of magnitude, reaching ∼0.64 ± 0.13 at room temperature, by means of arsenic ion implantation followed by low-temperature dopant activation. The dopant introduction employed represents a highly controllable doping technique used in standard silicon technology. It is found that the significant enhancement of ZT achieved is primarily due to a significant improvement of electrical conductivity by doping without crystallization so as to maintain the thermal conductivity and Seebeck coefficient at the level determined by the amorphous state of the silicon films. Our results open up a new route towards enabling a-Si as a prominent TE material for cost-efficient and environment-friendly TE applications at room temperature.

Energy harvesting

Thermoelectrics

Electrical conductivity

Electrical doping

Amorphous silicon

Author

Debashree Banerjee

Uppsala University

Central Electronics Engineering Research Institute

Örjan Vallin

Uppsala University

Majid Kabiri Samani

Chalmers, Microtechnology and Nanoscience (MC2), Electronics Material and Systems Laboratory

Subimal Majee

Uppsala University

Shi Li Zhang

Uppsala University

Johan Liu

Shanghai University

Chalmers, Microtechnology and Nanoscience (MC2), Electronics Material and Systems Laboratory

Zhi Bin Zhang

Uppsala University

Nano Energy

2211-2855 (ISSN)

Vol. 44 89-94

Subject Categories

Ceramics

Materials Chemistry

Other Materials Engineering

DOI

10.1016/j.nanoen.2017.11.060

More information

Latest update

4/11/2018