Growth and low-energy electron microscopy characterization of monolayer hexagonal boron nitride on epitaxial cobalt

Orofeo, Carlo M.; Suzuki, Satoru; Kageshima, Hiroyuki; Hibino, Hiroki

doi:10.1007/s12274-013-0310-1

Cited by 114 publications

(118 citation statements)

References 45 publications

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“…Whereas a maximum occur in the elastic spectra at about 7 eV (for 1 ML h-BN) or 8 eV (for 2 -4 ML h-BN), the inelastic effects produce sufficiently strong attentuation such that a minimum (for 1 ML) or very weak local maxima (for 2 -4 ML) are produced in the spectra at these energies. Our interpretation of the spectra is in agreement with that presented previously by Orofeo et al, 27 with our predicted reflectivity curves enabling a much more detailed understanding of the various spectral features. Again, proper treatment of inelastic effects is essential in producing spectra that can be compared to experiment.…”

Section: Hexagonal Boron Nitride On Cobaltsupporting

confidence: 92%

“…For our theoretical results of h-BN on Co, we similarly employ an oxide at the interface. 27 For this value of BN-O separation the reflectivity minimum for a single h-BN layer occurs at about 7.5 eV, compared to 6.5 eV in the experiment. With a subsequent h-BN layer, a minimum appears near 2 eV, comparable to the experiment.…”

Section: Hexagonal Boron Nitride On Cobaltmentioning

confidence: 66%

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Inelastic effects in low-energy electron reflectivity of two-dimensional materials

Gao

Mende

Widom

et al. 2014

Journal of Vacuum Science &Amp; Technology B, Nanotechnology and Microelectronics: Materials, Processing, Measurement, and Phen

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A simple method is proposed for inclusion of inelastic effects (electron absorption) in computations of low-energy electron reflectivity (LEER) spectra. The theoretical spectra are formulated by matching of electron wavefunctions obtained from first-principles computations in a repeated vacuum-slab-vacuum geometry. Inelastic effects are included by allowing these states to decay in time in accordance with an imaginary term in the potential of the slab, and by mixing of the slab states in accordance with the same type of distribution as occurs in a free-electron model. LEER spectra are computed for various two-dimensional materials, including freestanding multilayer graphene, graphene on copper substrates, and hexagonal boron nitride (h-BN) on cobalt substrates.

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Section: Hexagonal Boron Nitride On Cobaltsupporting

confidence: 92%

Section: Hexagonal Boron Nitride On Cobaltmentioning

confidence: 66%

Inelastic effects in low-energy electron reflectivity of two-dimensional materials

Gao

Mende

Widom

et al. 2014

Journal of Vacuum Science &Amp; Technology B, Nanotechnology and Microelectronics: Materials, Processing, Measurement, and Phen

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“…However, the flakes are obtained through a highly skilled manual process-mechanical exfoliation and transferring, which is not a scalable method for practical applications. So far, many efforts have been taken on various substrates such as Ni [16][17][18][19][20][21] , Cu 3,[21][22][23][24][25][26][27] , Pt 28,29 , Ru 30,31 and Co 32 to obtain large h-BN crystals via the chemical vapour deposition (CVD) process. However, those grains in h-BN films are very small (usually o50 mm 2 ) because of high nucleation density at the early growth stages 10,11,[15][16][17]19,22 .…”

mentioning

confidence: 99%

Synthesis of large single-crystal hexagonal boron nitride grains on Cu–Ni alloy

et al. 2015

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Hexagonal boron nitride (h-BN) has attracted significant attention because of its superior properties as well as its potential as an ideal dielectric layer for graphene-based devices. The h-BN films obtained via chemical vapour deposition in earlier reports are always polycrystalline with small grains because of high nucleation density on substrates. Here we report the successful synthesis of large single-crystal h-BN grains on rational designed Cu-Ni alloy foils. It is found that the nucleation density can be greatly reduced to 60 per mm 2 by optimizing Ni ratio in substrates. The strategy enables the growth of single-crystal h-BN grains up to 7,500 mm 2 , approximately two orders larger than that in previous reports. This work not only provides valuable information for understanding h-BN nucleation and growth mechanisms, but also gives an effective alternative to exfoliated h-BN as a high-quality dielectric layer for large-scale nanoelectronic applications.

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“…No discrete thickness oscillations are observed in connection with these minima; the oscillations found in the absence of inelastic e ects are eliminated when the inelastic e ects are included. Experimentally, a broad re ectivity minimum centered at about 8.2 eV above the vacuum level has indeed been observed in h-BN LEER spectra, [4,49] and two minima (or a minimum and a shoulder) are seen within that broad minimum. As mentioned in Section 3.2, for the computation of Fig.…”

Section: Reflectivitymentioning

confidence: 68%

“…For these reasons, LEEM is highly suited to studies of 2D materials and 2D heterostructures. There have been numerous LEEM studies of semimetallic graphene [43 48] and insulating hexagonal boron nitride, [4,49] but the expanding class of 2D semiconductors remains to be investigated in detail. [5,50,51] Here, we study atomically thin lms of WSe 2 , a semiconducting transition metal Since WSe 2 is a another layered material, it is a natural question to ask whether or not similar states exist between the quasi-2D layers of few-layer WSe 2 and can be counted by analyzing electron re ectivity.…”

Section: Introductionmentioning

confidence: 99%