journal article·2025-07-01Open access

1/f noise and two-level systems in MBE-grown Al thin films

Shouray Kumar Sahu, Yen-Hsun Glen Lin, Kuan-Hui Lai, Chao-Kai Cheng, Chun-Wei Wu, Elica Anne Heredia, Ray-Tai Wang, Yen-Hsiang Lin, Juainai Kwo, Minghwei Hong, Juhn-Jong Lin, Sheng-Shiuan Yeh

APL Materials· Volume 13· Issue 7

Abstract

Aluminum thin films are essential to the functionalities of electronic and quantum devices, where two-level systems (TLSs) can degrade device performance. Molecular beam epitaxy (MBE)-grown Al films may appeal to these applications due to their low TLS densities. We studied the energy distributions of TLS densities, g(E), in 10-nm-thick MBE-grown and electron-beam evaporated Al films through 1/f noise measurements between 80 and 360 K. At 300 K, the noise magnitudes in MBE-grown films are about three times lower than in the electron-beam evaporated films, corresponding to the g(E) values about ten times lower in the former than in the latter. Compared with previously established observations, we identified that the 1/f noise was generated by thermally activated TLS at grain boundaries.
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Research context

OpenAlex topics: Quantum and electron transport phenomena · Semiconductor materials and devices · Surface and Thin Film Phenomena

SciVX discovery tags are terminology-based. OpenAlex topics are source-provided classifications.

Affiliations

International College of Semiconductor Technology, National Yang Ming Chiao Tung University 1 , Hsinchu 30010,

Graduate Institute of Applied Physics and Department of Physics, National Taiwan University 2 , Taipei 106319,

Department of Electrophysics, National Yang Ming Chiao Tung University 3 , Hsinchu 30010,

Department of Physics, National Tsing Hua University 4 , Hsinchu 300044,

Center for Emergent Functional Matter Science, National Yang Ming Chiao Tung University 5 , Hsinchu 30010,

Funding

National Science and Technology Council

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