Reduction of Twin Boundary in NbN Films Grown on Annealed AlN
Reduction of Twin Boundary in NbN Films Grown on Annealed AlN
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DOI：
10.1021/acs.cgd.1c01287
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发表时间：
2022-01
影响因子：
3.8
通讯作者：
Shunya Kihira;A. Kobayashi;K. Ueno;H. Fujioka
中科院分区：
文献类型：
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作者：
Shunya Kihira;A. Kobayashi;K. Ueno;H. Fujioka
基于氮化铌（NbN）薄膜的超导纳米线单光子探测器（SNSPD）由于具有高的超导转变温度和快速的响应时间而受到广泛关注。氮化铝是一个合适的衬底，获得高质量的单晶NbN薄膜，因为它们之间的晶格失配小。然而，在AlN（0001）上生长的NbN（111）受到高密度孪晶界形成的影响。在这项研究中，我们使用原子级平坦的AlN衬底在1700 °C下退火，减少了NbN孪晶界。在退火的AlN上生长的NbN的无孪晶区扩展到了101 × 1 μm2。在这项研究中阐明的外延生长可能有助于制造大面积的NbN/AlN SNSPD没有结构缺陷。
Superconducting nanowire single-photon detectors (SNSPDs) based on ultrathin niobium nitride (NbN) films have attracted much attention owing to their high superconducting transition temperature and fast response time. AlN is a suitable substrate for obtaining high-quality single-crystal NbN films because of the small lattice mismatch between them. However, NbN(111) grown on AlN(0001) suffers from the formation of high-density twin boundaries. In this study, we reduce the NbN twin boundaries using atomically flat AlN substrates annealed at 1700 °C. The twin-boundary-free region of the NbN grown on the annealed AlN is extended to ∼1 × 1 μm2. The epitaxial growth elucidated in this study may contribute to the fabrication of large-area NbN/AlN SNSPDs without structural defects.