Band and Phonon Engineering for Thermoelectric Enhancements of Rhombohedral GeTe

doi:10.1021/acsami.9b07455

	Band and Phonon Engineering for Thermoelectric Enhancements of Rhombohedral GeTe
	Liu, Hongxia; Zhang, Xinyue; Li, Juan; Bu, Zhonglin; Meng, Xiang; Ang, Ran; Li, Wen
刊名	ACS APPLIED MATERIALS & INTERFACES
	2019-08-28
卷号	11 期号:34 页码:30756
关键词	thermoelectric rhombohedral GeTe band engineering phonon engineering average zT
ISSN号	1944-8244
DOI	10.1021/acsami.9b07455
文献子类	Article
英文摘要	Rhombohedral GeTe can be approximated as the directional distortion of the cubic GeTe along [111]. Such a symmetry-breaking of the crystal structure results in an opposite arrangement in energy of the L and Sigma valence bands, and a split of them into 3L+1Z and 6 Sigma+6 eta, respectively. This enables a manipulation of the overall band degeneracy for thermoelectric enhancements through a precise control of the degree of crystal structure deviating from a cubic structure for the alignment of the split bands. Here, we show the effect of AgBiSe2-alloying on the crystal structure as well as thermoelectric transport properties of rhombohedral GeTe. AgBiSe2 alloying is found to not only finely manipulate the crystal structure for band convergence and thereby an increased band degeneracy, but also flatten the valence band for an increased band effective mass. Both of them result in an increased density of state effective mass and therefore an enhanced Seebeck coefficient along with a decreased mobility. Moreover, a remarkably reduced lattice thermal conductivity of similar to 0.4 W/m-K is obtained due to the introduced additional point defect phonon scattering and bond softening by the alloying. With the help of Bi-doping at the Ge site for further optimizing the carrier concentration, thermoelectric figure of merit, zT, of similar to 1.7 and average zT(ave) of similar to 0.9 are achieved in 5% AgBiSe2-alloyed rhombohedral GeTe, which demonstrates this material as a promising candidate for low-temperature thermoelectric applications.
WOS研究方向	Science & Technology - Other Topics ; Materials Science
语种	英语
出版者	AMER CHEMICAL SOC
内容类型	期刊论文
源URL	[http://ir.sic.ac.cn/handle/331005/26888]
专题	中国科学院上海硅酸盐研究所
推荐引用方式 GB/T 7714	Liu, Hongxia,Zhang, Xinyue,Li, Juan,et al. Band and Phonon Engineering for Thermoelectric Enhancements of Rhombohedral GeTe[J]. ACS APPLIED MATERIALS & INTERFACES,2019,11(34):30756.
APA	Liu, Hongxia.,Zhang, Xinyue.,Li, Juan.,Bu, Zhonglin.,Meng, Xiang.,...&Li, Wen.(2019).Band and Phonon Engineering for Thermoelectric Enhancements of Rhombohedral GeTe.ACS APPLIED MATERIALS & INTERFACES,11(34),30756.
MLA	Liu, Hongxia,et al."Band and Phonon Engineering for Thermoelectric Enhancements of Rhombohedral GeTe".ACS APPLIED MATERIALS & INTERFACES 11.34(2019):30756.