High-quality, large-area MoSe₂ and MoSe₂/Bi₂Se₃ heterostructures on AlN(0001)/Si(111) substrates by molecular beam epitaxy

Abstract

Atomically-thin, inherently 2D semiconductors offer thickness scaling of nanoelectronic devices and excellent response to light for low-power versatile applications. Using small exfoliated flakes, advanced devices and integrated circuits have already been realized, showing great potential to impact nanoelectronics. Here, high-quality single-crystal MoSe2 is grown by molecular beam epitaxy on AlN(0001)/Si(111), showing the potential for scaling up growth to low-cost, large-area substrates for mass production. The MoSe2 layers are epitaxially aligned with the aluminum nitride (AlN) lattice, showing a uniform, smooth surface and interfaces with no reaction or intermixing, and with sufficiently high band offsets. High-quality single-layer MoSe2 is obtained, with a direct gap evidenced by angle-resolved photoemission spectroscopy and further confirmed by Raman and intense room temperature photoluminescence. The successful growth of high-quality MoSe2/Bi2Se3 multilayers on AlN shows promise for novel devices exploiting the non-trivial topological properties of Bi2Se3.

Two-dimensional semiconductor HfSe2 and MoSe2/HfSe2 van der Waals heterostructures by molecular beam epitaxy

“…azimuthially aligned (Fig. 1), suggesting that the epilayers are epitaxially grown such that [11][12][13][14][15][16][17][18][19][20] 6,7,16 indicating the absence of strain as would be expected in van der Waals heteroepitaxy 17,18 of these materials.…”

“…14,15 It should be noted here that reversing the order of the epitaxy such that the MoSe 2 is grown first on AlN followed by HfSe 2 overgrowth is also an option. However, emphasis is given on the direct order (MoSe 2 /HfSe 2 /AlN) because MoSe 2 is much more stable in air against oxidation 15 compared to HfSe 2 13 and essentially serves as a protective cap during processing of the bilayer for device fabrication.…”

Millimeter-scale layered MoSe2 grown on sapphire and evidence for negative magnetoresistance

“…However, the TMDs layers obtained by this method show an inhomogeneity and discontinuous nature due to the absence of precise thickness control. Molecular beam epitaxy (MBE) is of particular interest because one can achieve high purity of the layers, precise control of the thickness, flexible choice of metals and scalability [12,13]. Since a single layer of TMDs is separated from each other by an out-of-plane van der Waals gap, interactions between TMDs layers and a chemically passivated substrate are expected to be of van der Waals type.…”

Growth of Transition Metal Dichalcogenides and Directly Modulating Their Properties by Chemical Vapor Deposition

“…[112] Besides, other method such as molecular beam epitaxy (MBE), combined with CVD, can also realize other van del Waals heterostructures. [114][115][116][117][118] It should be noted that diverse TMDs can form diverse heterostructures, and more novel properties are still needed to be investigated further. The CVD synthesis of heterostructures based on TMDs is just the first step.…”