Effective enhancement of thermoelectric and mechanical properties of germanium telluride via rhenium-doping. Issue 47 (11th November 2020)

• Record Type: Journal Article
• Authors: Suwardi, Ady; Lim, Su Hui; Zheng, Yun; Wang, Xizu; Chien, Sheau Wei; Tan, Xian Yi; Zhu, Qiang; Wong, Lai Mun Nancy; Cao, Jing; Wang, Weide; Yan, Qingyu; Tan, Chee Kiang Ivan; Xu, Jianwei
• Is Part Of: Journal of materials chemistry. Volume 8:Issue 47(2020)
• Page Start: 16940
• Page End: 16948
• Publication Date: 2020-11-11
• Subjects: Materials -- Periodicals; Chemistry, Analytic -- Periodicals; Optical materials -- Research -- Periodicals; Electronics -- Materials -- Research -- Periodicals; 543.0284
• DOI: 10.1039/d0tc04903d
• Languages: English
• ISSNs: 2050-7526

Abstract

Abstract : The introduction of 2% rhenium into GeTe leads to the remarkable enhancement of Vickers microhardness from 145 to 342 MPa, as well as a 16.5% improvement in Young's modulus but not at the expense of thermoelectric properties. Abstract : GeTe as one of the most promising medium temperature thermoelectrics has progressed leaps and bounds in recent years, largely thanks to a combination of its unique electronic, thermal and structural properties. Despite its various advantages, a major factor standing in the way of wide commercial adoptions lies in its unreliable mechanical properties. This work reports Re doping as a strategy to drastically enhance the mechanical properties of GeTe, resulting in Vickers microhardness as high as 342.6 Hv in Ge0.88 Sb0.10 Re0.02 Te, which is more than double that of pristine GeTe (145 Hv ). Ge0.88 Sb0.10 Re0.02 Te also exhibited a Young's modulus of 64.1 GPa, substantially higher than many other binary chalcogenide thermoelectrics. The significant enhancement of GeTe in mechanical properties is mainly related to the mechanism of precipitation hardening. In addition, we found that while the electronic properties were slightly compromised with Re doping, the lattice thermal conductivity was reduced due to point defects scattering brought about by Re atoms. Therefore, a high zT value (>1.6) at 600–800 K is achieved in Ge0.88 Sb0.10 Re0.02 Te. Furthermore, above 10% device efficiency can be expected for the operating temperature between 300–800 K. Such a solution to strengthen the mechanical properties of GeTe using Re doping is expected to play a major part in the push for full-scale GeTe-based thermoelectric devices.