Wang Zhenyi, Fu Chenguang, Xia Kaiyang, Liu Feng, Zhao Xinbing, Zhu Tiejun
State Key Laboratory of Silicon Materials, and School of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, China.
ACS Appl Mater Interfaces. 2021 Feb 17;13(6):7317-7323. doi: 10.1021/acsami.0c21813. Epub 2021 Feb 3.
In recent years, high-performance half-Heusler compounds have been developed as promising thermoelectric materials for power generation. Aiming at practical device applications, one key step is to seek suitable metal electrodes so that low interfacial resistivity is guaranteed under long-term thermal aging. In the previous work, the fresh Mo/NbTiFeSb junction was found exhibiting low contact resistivity below 1 μΩ cm; however, it increased by tens of times under long-term thermal aging, mainly originating from the formation of the high-resistivity FeSb phase and the appearance of cracks. Here, the Mo-Fe electrodes are employed to build the junctions with NbTiFeSb. The interfacial behavior and contact resistance in these junctions were investigated both before and after the thermal aging. Interestingly, no obvious formation of FeSb phase and cracks were observed. As a result, the contact resistivity was below ∼1 μΩ cm after 15 days' thermal aging, indicating better connection reliability and lower contact resistivity compared to the Mo/NbTiFeSb junction. These findings highlight the applicability of Mo-Fe electrodes and pave the way for NbFeSb-based half-Heusler thermoelectric materials for device applications.
近年来，高性能半赫斯勒化合物已被开发成为很有前景的用于发电的热电材料。针对实际器件应用，关键的一步是寻找合适的金属电极，以便在长期热老化条件下保证低界面电阻率。在先前的工作中，发现新鲜的Mo/NbTiFeSb结表现出低于1 μΩ·cm的低接触电阻率；然而，在长期热老化下它增加了数十倍，这主要源于高电阻率FeSb相的形成和裂纹的出现。在此，采用Mo-Fe电极与NbTiFeSb构建结。对这些结在热老化前后的界面行为和接触电阻进行了研究。有趣的是，未观察到明显的FeSb相形成和裂纹。结果，经过15天热老化后接触电阻率低于约1 μΩ·cm，这表明与Mo/NbTiFeSb结相比，连接可靠性更好且接触电阻率更低。这些发现突出了Mo-Fe电极的适用性，并为基于NbFeSb的半赫斯勒热电材料用于器件应用铺平了道路。
