We investigate the anisotropy in thermoelectric transport properties of pristine and self-doped InTe after spark plasma sintering and ascribe the observed weak anisotropy to the lack in orientation preference of investigated specimens as characterized by the scanning electron microscope. Then, the effect of Cu/Na doping on the transport properties of InTe is discussed for comparison, which suggests Cu doping is more favorable for keeping decent carrier mobility than Na doping and In-deficiency. Such difference is qualitatively explained by the large electronic affinity of Cu as compared to Na, which can effectively weaken the Coulomb scattering for charge carriers. Finally, a maximum figure of merit zT of about 0.73 at 730 K is obtained for the compound with the nominal composition of In_0.99Cu_0.01Te, measured parallel to the pressing direction, which can be attributed to the enhanced carrier concentration and well-maintained mobility compared to the pristine specimen. Furthermore, the Cu-doped specimen shows a superior average zT about 0.34, more than 35% enhancement than that for both Na-doped and self-doped InTe compounds. Our results should provide a guidance for selecting dopants for thermoelectric materials that possess strong ionized-impurity scattering character.

我们研究了原始等离子体和自掺杂InTe在火花等离子体烧结后的热电传输特性中的各向异性，并将所观察到的弱各向异性归因于扫描电子显微镜表征的缺乏被测样品的取向偏好。然后，为了比较，讨论了Cu / Na掺杂对InTe的传输性质的影响，这表明Cu掺杂比Na掺杂和In-缺乏更有利于保持良好的载流子迁移率。与Na相比，Cu与Na的电子亲和力大，从质上解释了这种差异，这可以有效地削弱电荷载流子的库仑散射。最后，对于标称组成为In _0.99的化合物，在730 K下获得的最大品质因数zT约为0.73平行于压制方向测量的Cu _0.01 Te，与原始样品相比，可以归因于提高的载流子浓度和良好的迁移率。此外，掺杂铜的试样显示出的平均zT值约为0.34，比掺Na和自掺杂InTe化合物的zT值高出35％以上。我们的结果应为选择具有强电离杂质散射特性的热电材料选择掺杂剂提供指导。