Realization of independent contacts in barrier-separated InAs/GaSb quantum wells
Realization of independent contacts in barrier-separated InAs/GaSb quantum wells
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DOI：
10.1063/5.0133795
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发表时间：
2023-03
影响因子：
4
通讯作者：
Xingjun Wu;Jianhuan Wang;Miaoling Huang;Shili Yan;R. Du
中科院分区：
文献类型：
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作者：
Xingjun Wu;Jianhuan Wang;Miaoling Huang;Shili Yan;R. Du
用分子束外延技术生长了InAs/GaSb双量子威尔斯阱，中间用100 μ m的AlSb中间势垒隔开。我们报告了一种纳米结构技术，利用表面费米能级钉扎位置InAs [公式：见正文]实现独立的电接触到每个井。特别是，单独的欧姆接触的上部InAs量子阱是通过选择性地蚀刻到InAs，而接触的下部GaSb量子阱是通过耗尽方法获得的。对于后者，上部InAs量子阱被覆盖有剩余的2-3 nm InAs层的顶部蚀刻沟槽局部夹断。由于相对较低的[公式：见正文]，施加负偏置栅极电位将在GaSb中创建导电空穴沟道，因此，与较低量子阱形成单独的欧姆接触。这种方法证明了与实验和支持的自洽带弯曲计算。一些分别探测库仑和隧道耦合的InAs/GaSb系统的实验现在变得容易。
InAs/GaSb double quantum wells separated by a 100 Å AlSb middle barrier are grown by molecular beam epitaxy. We report a nanofabrication technique that utilizes the surface Fermi level pinning position in InAs [Formula: see text] for realizing independent electric contacts to each well. In particular, separate Ohmic contacts to the upper InAs quantum well are achieved by selectively etching down to the InAs, while contacts to the lower GaSb quantum well are obtained by the depletion method. For the latter, the upper InAs quantum well is locally pinched off by top etched trenches capped with a remaining 2–3 nm InAs layer. As a result of a relatively low [Formula: see text], applying a negative bias gate potential will create a conducting hole channel in GaSb and, hence, a separate Ohmic contact to the lower quantum well. This method is demonstrated with experiment and the support of a self-consistent band bending calculation. A number of experiments on separately probing Coulomb and tunnel-coupled InAs/GaSb systems now become accessible.