Interfacial Engineering of Semiconductor-Superconductor Junctions for High Performance Micro-Coolers.
Interfacial Engineering of Semiconductor-Superconductor Junctions for High Performance Micro-Coolers.
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DOI：
10.1038/srep17398
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发表时间：
2015-12-01
影响因子：
4.6
通讯作者：
Prunnila M
中科院分区：
文献类型：
--
作者：
Gunnarsson D;Richardson-Bullock JS;Prest MJ;Nguyen HQ;Timofeev AV;Shah VA;Whall TE;Parker EHC;Leadley DR;Myronov M;Prunnila M
通过材料界面控制电子和热传输对于许多微电子和纳米电子应用以及量子器件至关重要。在这里，我们报告的工程的电热性能的超导体（Sm-S）电子冷却器结的纳米绝缘隧道势垒之间引入的Sm和S电极。出乎意料的是，这样的界面势垒不增加结电阻，但大大降低了有害的子间隙漏电流。这些功能是实现高冷却功率隧道结制冷机的关键，我们展示了无与伦比的性能，在硅基Sm-S电子冷却器设备与数量级的改善，在冷却功率相比，以前的作品。通过调整应变工程硅冷却器中的结，我们还证明了有效的电子温度从300 mK降低到100 mK以下。对具有不同界面质量的结的研究表明，Sm-S界面态对以前无法解释的子带隙漏电流有很大的影响。这些状态通常通过众所周知的费米能级钉扎效应来决定结电阻，因此，超导性通常可以用于探测和优化金属-半导体接触行为。
The control of electronic and thermal transport through material interfaces is crucial for numerous micro and nanoelectronics applications and quantum devices. Here we report on the engineering of the electro-thermal properties of semiconductor-superconductor (Sm-S) electronic cooler junctions by a nanoscale insulating tunnel barrier introduced between the Sm and S electrodes. Unexpectedly, such an interface barrier does not increase the junction resistance but strongly reduces the detrimental sub-gap leakage current. These features are key to achieving high cooling power tunnel junction refrigerators, and we demonstrate unparalleled performance in silicon-based Sm-S electron cooler devices with orders of magnitudes improvement in the cooling power in comparison to previous works. By adapting the junctions in strain-engineered silicon coolers we also demonstrate efficient electron temperature reduction from 300 mK to below 100 mK. Investigations on junctions with different interface quality indicate that the previously unexplained sub-gap leakage current is strongly influenced by the Sm-S interface states. These states often dictate the junction electrical resistance through the well-known Fermi level pinning effect and, therefore, superconductivity could be generally used to probe and optimize metal-semiconductor contact behaviour.