Oxygen-Induced In Situ Manipulation of the Interlayer Coupling and Exciton Recombination in Bi₂Se₃/MoS₂ 2D Heterostructures

Abstract

2D heterostructures are more than a sum of the parent 2D materials, but are also a product of the interlayer coupling, which can induce new properties. In this paper we present a method to tune the interlayer coupling in Bi2Se3/MoS2 2D heterostructures by regulating the oxygen presence in the atmosphere, while applying laser or thermal energy. Our data suggests the interlayer coupling is tuned through the diffusive intercalation and de-intercalation of oxygen molecules. When one layer of Bi2Se3 is grown on monolayer MoS2, an influential interlayer coupling is formed that quenches the signature photoluminescence (PL) peaks. However, thermally annealing in the presence of oxygen disrupts the interlayer coupling, facilitating the emergence of the MoS2 PL peak. DFT calculations predict intercalated oxygen increases the interlayer separation ~17%, disrupting the interlayer coupling and inducing the layers to behave more electronically independent. The interlayer coupling can then be restored by thermally annealing in N2 or Ar, where the peaks will re-quench. Hence, this is an interesting oxygen-induced switching between "non-radiative" and "radiative" exciton recombination. This switching can also be accomplished locally, controllably, and reversibly using a lowpower focused laser, while changing the environment from pure N2 to air. This allows for the interlayer coupling to be precisely manipulated with submicron spatial resolution, facilitating site-programmable 2D light-emitting pixels whose emission intensity could be precisely varied by a factor exceeding 200×. Our results show that these atomically-thin 2D heterostructures may be excellent candidates for oxygen sensing.

Band alignment of type-I SnS2/Bi2Se3 and type-II SnS2/Bi2Te3 van der Waals heterostructures for highly enhanced photoelectric responses

“…2e shows the Raman spectra of Bi 2 Se 3 , SnS 2, and their heterostructures. The characteristic peaks of Bi 2 Se 3 near 129 and 174 cm −1 accord with the E g and A 1g vibration modes of Bi 2 Se 3 , respectively [18]. The single peak near 313 cm −1 in the spectrum of SnS 2 is consistent with the A 1g vibration mode of SnS 2 .…”

“…2D layered narrow-band-gap materials are outstanding heterogeneous components by virtue of their active edges, wide absorption range (up to infrared light), and high carrier mobility. For example, Bi 2 Se 3 and Bi 2 Te 3 show narrow band gaps (0.3-1.0 eV) [18,19], conductive surface states, and high specific surface areas. Furthermore, Bi 2 Se 3 and Bi 2 Te 3 are typical topologically insulator-layered materials [20,21] with an outer spinmomentum-locked Dirac cone and an internal insulating band gap [22].…”

“…Especially, Bi 2 X 3 (X = Se, Te) materials can be easily synthesized by physical vapor deposition (PVD) adopting a van der Waals (vdW) approach. The resulting 2D materials are high-quality and have large areas [18,19]. Unlike traditional heterostructures, 2D vdW heterostructures can be easily constructed without the limitations of lattice matching.…”

In Situ Characterization of Transformations in Nanoscale Layered Metal Chalcogenide Materials: A Review

“…Recently, oxygen was also shown to be useful to control the interlayer coupling between vdW heterostructures. For example, Hennighausen et al [122] showed that impinging a low-power laser on a Bi 2 Se 3 /MoS 2 heterostructure in an oxygen-containing environment reduced the interlayer coupling effect on photoluminescence response. This is evidenced by the tunable photoluminescence (PL) spectrum whose intensity increases with increasing laser exposure time.…”

Modified Absorption and Emission Properties Leading to Intriguing Applications in Plasmonic–Excitonic Nanostructures

“…Other studies also reported fluorescence enhancement in semiconductor nanostructures doped films supported by plasmonic nanostructures. [304,305] In addition to these, other approaches like defect passivation, [306] oxygen intercalation, [307] and strain bandgap engineering [308] have also been successfully employed to enhance PL intensity. Figure 15f illustrates the deviation in PL intensity with changing polarization angle.…”