Synthesis and transport properties of epitaxial Bi (111) films on GaAs (111) substrates.

Journal Article · Thu Feb 12 00:00:00 UTC 2026 · APL materials

DOI: https://doi.org/10.1063/5.0304277 · OSTI ID:3363822

Jena, Jagannath; Ark, Eugene D.; Ambhire, Siddhesh; Smith, Michael D.; Woods, Justin S.; Yang, Junyi; Pearson, John ; Arava, Hanu; Rosenmann, Daniel; Welp, Ulrich; Jiang, Jidong S.; Hong, Deshun; Martin, Ivar; Zhang, Steven S.-L.; Bhattacharya, Anand

In recent decades, the growth of ultrathin epitaxial bismuth (Bi) films on various substrates has garnered interest due to their unique electronic properties. We report upon the growth and electrical transport properties of epitaxial Bi (111) films in the thickness range of 5-32 nm deposited directly on GaAs (111) substrates, without a buffer layer. The quality of Bi films is found to depend on conditions for substrate treatment using Ar+ ion-milling and annealing. Substrates milled at low ion beam currents display poor surface reconstruction after annealing, which hinders the growth of high-quality films. In contrast, substrates milled under optimized conditions led to reconstructed surfaces upon annealing, resulting in epitaxial Bi films with predominantly single-domain orientation. Although epitaxial films formed in both cases, transport measurements indicated significantly higher conductivity for films grown on optimally treated substrates. Measurements at low temperatures suggest that the transport properties are dominated by a surface state with high mobility electrons. Magneto-transport measurements suggest that conductivity and mobility improve progressively with increasing film thickness. For the thinnest 5 nm film, a hole-like state emerges, presumably as the electron-like state is gapped out. These results provide a robust methodology for growing high-quality epitaxial Bi films on GaAs (111) and offer insights into their unique transport properties and our ability to tune them.

• Research Organization: Argonne National Laboratory (ANL)
• Sponsoring Organization: Case Western Reserve University; US Department of Energy; USDOE Office of Science - Energy Frontier Research Center; USDOE Office of Science - Office of Basic Energy Sciences; USDOE Office of Science - Office of Basic Energy Sciences - Scientific User Facilities Division
• Grant/Contract Number: AC02-06CH11357
• OSTI ID: 3363822
• Journal Information: APL materials, Journal Name: APL materials Journal Issue: 1 Vol. 14
• Country of Publication: United States
• Language: English