Growth of Bi.sub.2Se.sub.3/graphene heterostructures with the room temperature high carrier mobility

• Published in: Journal of materials science 2021-05, Vol.56 (15), p.9330
• Main Authors: Antonova, I. V, Nebogatikova, N. A, Stepina, N. P, Volodin, V. A, Kirienko, V. V, Rybin, M. G, Obrazstova, E. D
• Format: Article
• Language: English
• Subjects: Chemical vapor deposition; Electric properties; Epitaxy; Graphene; Graphite; Signal processing
• ISSN: 0022-2461; 1573-4803
• DOI: 10.1007/s10853-021-05836-y

Heterostructures of Bi.sub.2Se.sub.3 topological insulators were epitaxially grown on graphene by means of the physical vapor deposition at 500 °C. Micrometer-sized flakes with thickness 1 QL (quintuple layer ~ 1 nm) and films of millimeter-scale with thicknesses 2-6 QL had been grown on CVD graphene. The minimum thickness of large-scaled continuous Bi.sub.2Se.sub.3 films was found to be ~ 8 QL for the regime used. The heterostructures with a Bi.sub.2Se.sub.3 film thickness of > 10 QL had resistivity as low as 200-500 â¦/sq and a high room temperature carrier mobility ~ 1000-3400 cm.sup.2/Vs in the Bi.sub.2Se.sub.3/graphene interface channel. Moreover, the coexistence of a p-type graphene-related conductive channel, simultaneously with the n-type conductive surface channel of Bi.sub.2Se.sub.3, was observed. The improvement of the bottom Bi.sub.2Se.sub.3/graphene interface with the increase in the growth time clearly manifested itself in the increase of conductivity and carrier mobility in the grown layer. The grown Bi.sub.2Se.sub.3/G structures have lower resistivities and more than one order of magnitude higher carrier mobilities in comparison with the van der Waals Bi.sub.2Se.sub.3/graphene heterostructures created employing exfoliation of thin Bi.sub.2Se.sub.3 layers. The grown heterostructures demonstrated the properties that are perspective for new functional devices, for a variety of signal processing and logic applications.