InSe as a case between 3D and 2D layered crystals for excitons

Shubina, T. V.; Desrat, Wilfried; Moret, Matthieu; Tiberj, Antoine; Briot, Olivier; Davydov, V. Yu.; Platonov, A. V.; Semina, M. A.; Gil, Bernard

doi:10.1038/s41467-019-11487-0

Cited by 46 publications

(53 citation statements)

References 48 publications

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“…The highest-energy peak observed in the PL spectrum at T = 11 K is detected at ~1.307 eV. This is more than 30 meV lower than the exciton recombination line (1.338 eV) recently reported by Shubina et al [ 94 ] for flakes freshly cleaved from high structural quality bulk InSe grown by the Bridgman–Stockbarger method. According to the previous results [ 95 , 96 ], in the region below 1.32 eV, three main broad bands around 1.31, 1.28, and 1.23 eV have been reported in undoped InSe, which were assigned to impurity-band, donor–acceptor pair, and impurity-vacancy complex transitions, respectively.…”

Section: Resultsmentioning

confidence: 54%

Molecular Beam Epitaxy of Layered Group III Metal Chalcogenides on GaAs(001) Substrates

et al. 2020

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Development of molecular beam epitaxy (MBE) of two-dimensional (2D) layered materials is an inevitable step in realizing novel devices based on 2D materials and heterostructures. However, due to existence of numerous polytypes and occurrence of additional phases, the synthesis of 2D films remains a difficult task. This paper reports on MBE growth of GaSe, InSe, and GaTe layers and related heterostructures on GaAs(001) substrates by using a Se valve cracking cell and group III metal effusion cells. The sophisticated self-consistent analysis of X-ray diffraction, transmission electron microscopy, and Raman spectroscopy data was used to establish the correlation between growth conditions, formed polytypes and additional phases, surface morphology and crystalline structure of the III–VI 2D layers. The photoluminescence and Raman spectra of the grown films are discussed in detail to confirm or correct the structural findings. The requirement of a high growth temperature for the fabrication of optically active 2D layers was confirmed for all materials. However, this also facilitated the strong diffusion of group III metals in III–VI and III–VI/II–VI heterostructures. In particular, the strong In diffusion into the underlying ZnSe layers was observed in ZnSe/InSe/ZnSe quantum well structures, and the Ga diffusion into the top InSe layer grown at ~450 °C was confirmed by the Raman data in the InSe/GaSe heterostructures. The results on fabrication of the GaSe/GaTe quantum well structures are presented as well, although the choice of optimum growth temperatures to make them optically active is still a challenge.

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Section: Resultsmentioning

confidence: 54%

Molecular Beam Epitaxy of Layered Group III Metal Chalcogenides on GaAs(001) Substrates

et al. 2020

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“…3b). The PL peak energy corresponds to that of the band-edge exciton 21,22 and is very sensitive to the layer thickness: it increases from E X~1 .28 eV for t = 19 layers to E X~1 .39 eV for t = 8 layers. Figure 3c shows the I-V SD and G-V SD curves of these three devices, revealing that the current and voltage spacing between consecutive resonances increases with decreasing t. We note that no resonances were observed in the device with t = 19 layers or in other devices with thicker layers.…”

Section: Resultsmentioning

confidence: 99%

Resonant tunnelling into the two-dimensional subbands of InSe layers

et al. 2020

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Two-dimensional (2D) van der Waals (vdW) crystals have attracted considerable interest for digital electronics beyond Si-based complementary metal oxide semiconductor technologies. Despite the transformative success of Si-based devices, there are limits to their miniaturization and functionalities. Here we realize a resonant tunnelling transistor (RTT) based on a 2D InSe layer sandwiched between two multilayered graphene (MLG) electrodes. In the RTT the energy of the quantum-confined 2D subbands of InSe can be tuned by the thickness of the InSe layer. By applying a voltage across the two MLG electrodes, which serve as the source and drain electrodes to the InSe, the chemical potential in the source can be tuned in and out of resonance with a given 2D subband, leading to multiple regions of negative differential conductance that can be additionally tuned by electrostatic gating. This work demonstrates the potential of InSe and InSe-based RTTs for applications in quantum electronics.

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“…These spectra were gathered 5 months after the initial exposure to the Kaufman source. The multiple emission lines at low photon energies (<1.32 eV) are most prominent at low excitation powers and are associated with impurities and/or defects [41,42]. No features at photon energies less than 1.32 eV can be successfully attributed to hydrogen, as the variation between the two samples is indistinguishable from the variation found within the individual samples.…”

Section: Photoluminescencementioning

confidence: 92%

“…No features at photon energies less than 1.32 eV can be successfully attributed to hydrogen, as the variation between the two samples is indistinguishable from the variation found within the individual samples. For photon energies above 1.32 eV, the exciton (X), biexciton (XX) and exciton-exciton scattering (X-X) PL lines can be identified [41,42]. They dominate the PL spectra at high excitation powers.…”

Section: Photoluminescencementioning

confidence: 99%

The Interaction of Hydrogen with the van der Waals Crystal γ-InSe

et al. 2020

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The emergence of the hydrogen economy requires development in the storage, generation and sensing of hydrogen. The indium selenide ( γ -InSe) van der Waals (vdW) crystal shows promise for technologies in all three of these areas. For these applications to be realised, the fundamental interactions of InSe with hydrogen must be understood. Here, we present a comprehensive experimental and theoretical study on the interaction of γ -InSe with hydrogen. It is shown that hydrogenation of γ -InSe by a Kaufman ion source results in a marked quenching of the room temperature photoluminescence signal and a modification of the vibrational modes of γ -InSe, which are modelled by density functional theory simulations. Our experimental and theoretical studies indicate that hydrogen is incorporated into the crystal preferentially in its atomic form. This behaviour is qualitatively different from that observed in other vdW crystals, such as transition metal dichalcogenides, where molecular hydrogen is intercalated in the vdW gaps of the crystal, leading to the formation of “bubbles” for hydrogen storage.

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InSe as a case between 3D and 2D layered crystals for excitons

Cited by 46 publications

References 48 publications

Molecular Beam Epitaxy of Layered Group III Metal Chalcogenides on GaAs(001) Substrates

Molecular Beam Epitaxy of Layered Group III Metal Chalcogenides on GaAs(001) Substrates

Resonant tunnelling into the two-dimensional subbands of InSe layers

The Interaction of Hydrogen with the van der Waals Crystal γ-InSe

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