摘要
用高温熔融结合放电等离子烧结法制备了Zn掺杂单相n型Ba8Ga16-2xZnx Ge30+x笼合物,探索了Zn对Ga的取代对其热电传输特性的影响规律.研究结果表明,n型Ba8Ga16-2xZnxGe30+x化合物的电导率随着x的增加逐渐增大,Seebeck系数随着x的增加而逐渐减小.当Zn完全取代Ga时,Ba8Zn8Ge38化合物的电导率反而急剧下降,Seebeck系数显著增大.Ba8Ga16-2xZnxGe30+x化合物的载流子迁移率随着温度的升高而降低,当Zn掺杂后,化合物的载流子迁移率有一定的增加,随着x的增加而逐渐增大.Ba8Ga16-2xZnxGe30+x化合物的热导率和晶格热导率变化规律类似,随着x的增加先减小后增大.在所有n型Ba8Ga16-2xZnxGe30+x笼合物中,Ba8Ga8Zn4Ge34化合物的ZT值最大,在1000K时其最大ZT值达0·85.
The single-phase Zn-doped n-type Ba8Ga16-2xZnxGe30＋ clathrates were prepared by melting reaction method combined with spark plasma sintering （SPS）. Influences of substituting Zn for Ga on the thermoelectric transport properties of the compounds were investigated. Research results indicate that the electrical conductivity of n-type Ba8Ga16-2xZnxGe30＋ compounds increases gradually with the increasing of Zn substitution fraction x. The Seebeck coefficient decreases gradually with the increasing of x. When Zn replaces Ga entirely, the electrical conductivity of Bas Zns Ge3s compound drops rapidly and its Seebeck coefficient increases suddenly. Zn substitution fraction x dependence of the thermal conductivity and lattice thermal conductiyity are similar in the temperature range from 300 to 1000 K. When x 〈 4, with the increasing of x, lattice thermal conductivity decreases gradually. When x 〉 4, with the increase of x, lattice thermal conductivity increases gradually. In all n-typeBa8Ga16-2xZnxGe30＋ clathrates, BasGasZn4Ge34 compound has the greatest ZT value, and its maximal ZT value reaches 0.85 at about 1000 K.
出处
《物理学报》
SCIE
EI
CAS
CSCD
北大核心
2008年第2期1190-1196,共7页
Acta Physica Sinica
基金
国家自然科学基金重大国际合作项目(批准号:50310353)
国家自然科学基金(批准号:50572082)资助的课题.~~
关键词
热电传输性能
n型笼合物
框架取代
thermoelectric transport properties, n-type clathrate compounds, framework substitution
