Scalable Characterization of 2D Gallium-Intercalated Epitaxial Graphene

Hesham El-Sherif, Natalie Briggs, Brian Bersch, Minghao Pan, Mahdi Hamidinejad, Siavash Rajabpour, Tobin Filleter, Ki Wook Kim, Joshua Robinson, Nabil D. Bassim

Research output: Contribution to journalArticlepeer-review

3 Scopus citations


Scalable synthesis of two-dimensional gallium (2D-Ga) covered by graphene layers was recently realized through confinement heteroepitaxy using silicon carbide substrates. However, the thickness, uniformity, and area coverage of the 2D-Ga heterostructures have not previously been studied with high-spatial resolution techniques. In this work, we resolve and measure the 2D-Ga heterostructure thicknesses using scanning electron microscopy (SEM). Utilizing multiple correlative methods, we find that SEM image contrast is directly related to the presence of uniform bilayer Ga at the interface and a variation of the number of graphene layers. We also investigate the origin of SEM contrast using both experimental measurements and theoretical calculations of the surface potentials. We find that a carbon buffer layer is detached due to the gallium intercalation, which increases the surface potential as an indication of the 2D-Ga presence. We then scale up the heterostructure characterization over a few-square millimeter area by segmenting SEM images, each acquired with nanometer-scale in-plane resolution. This work leverages the spectroscopic imaging capabilities of SEM that allows high-spatial resolution imaging for tracking intercalants, identifying relative surface potentials, determining the number of 2D layers, and further characterizing scalability and uniformity of low-dimensional materials.

Original languageEnglish (US)
Pages (from-to)55428-55439
Number of pages12
JournalACS Applied Materials and Interfaces
Issue number46
StatePublished - Nov 24 2021

All Science Journal Classification (ASJC) codes

  • General Materials Science


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