Synthesis and transport properties of epitaxial Bi (111) films on GaAs (111) substrates
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2025
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| author | Jena, Jagannath Ark, Eugene D. Ambhire, Siddhesh Smith, Michael D. Wood, 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 |
| author_facet | Jena, Jagannath Ark, Eugene D. Ambhire, Siddhesh Smith, Michael D. Wood, 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 |
| contents | 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. |
| format | Preprint |
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arxiv_https___arxiv_org_abs_2507_03301 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Synthesis and transport properties of epitaxial Bi (111) films on GaAs (111) substrates Jena, Jagannath Ark, Eugene D. Ambhire, Siddhesh Smith, Michael D. Wood, 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 Materials Science Mesoscale and Nanoscale Physics 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. |
| title | Synthesis and transport properties of epitaxial Bi (111) films on GaAs (111) substrates |
| topic | Materials Science Mesoscale and Nanoscale Physics |
| url | https://arxiv.org/abs/2507.03301 |