Epitaxy

Large-area growth of continuous transition metal dichalcogenides (TMDCs) layers is a prerequisite to transfer their exceptional electronic and optical properties into practical devices. It still represents an open issue nowadays. Electric and magnetic doping of TMDC layers to develop basic devices such as p-n junctions or diluted magnetic semiconductors for spintronic applications are also an important field of investigation. Here, we have developed two different techniques to grow MoSe 2 mono-and multi-layers on SiO 2 /Si substrates over large areas. First, we co-deposited Mo and Se atoms on SiO 2 /Si by molecular beam epitaxy in the van der Waals regime to obtain continuous MoSe 2 monolayers over 1 cm 2 . To grow MoSe 2 multilayers, we then used the van der Waals solid phase epitaxy which consists in depositing an amorphous Se/Mo bilayer on top of a co-deposited MoSe 2 monolayer which serves as a van der Waals growth template. By annealing, we obtained continuous MoSe 2 multilayers over 1 cm 2 . Moreover, by inserting a thin layer of Mn in the stack, we could demonstrate the incorporation of up to 10 % of Mn in MoSe 2 bilayers. * Electronic address: matthieu.jamet@cea.fr 1 arXiv:1906.03014v1 [cond-mat.mtrl-sci]

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“…The substrate is then heated to crystallize the film. The single crystal substrate serves here as a template for crystal growth [48].…”

Section: Growth Of Mose 2 By Van Der Waals-solid Phase Epitaxymentioning

confidence: 99%

Van der Waals solid phase epitaxy to grow large-area manganese-doped MoSe ₂ few-layers on SiO ₂ /Si

et al. 2019

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“…1 In this framework, organic molecular beam epitaxy ͑OMBE͒ represents the best choice among the growth techniques, assuring high quality films and controlled interfaces in organic heterostructures in view of both fundamental studies and applications. 3,4 Among the strategies for growing samples with designed properties, one of the most promising is the use of organic substrates [5][6][7] whose effect in tuning the molecular orientation of the overlayer has been already demonstrated. In particular, when organic single crystals are used as substrates, highly oriented organic heterostructures are grown even in the absence of any geometric coincidence between substrate and overlayer ͑incommensurate epitaxy͒.…”

Section: Dipartimento DI Scienza Dei Materiali and Cnism Università mentioning

confidence: 99%

Pseudomorphic growth of organic semiconductor thin films driven by incommensurate epitaxy

Sassella

Campione

Raimondo

et al. 2009

Applied Physics Letters

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A stable pseudomorphic phase of ␣-quaterthiophene, a well known organic semiconductor, is obtained by growing films with organic molecular beam epitaxy ͑OMBE͒ on a single crystal of another organic semiconductor, namely, tetracene. The structural characteristics of the new phase are investigated by monitoring in situ the OMBE process by reflectance anisotropy spectroscopy; thus assessing that incommensurate epitaxy is in this case, the driving force for tuning the molecular packing in organic molecular films and in turn, their solid state properties. © 2009 American Institute of Physics. ͓DOI: 10.1063/1.3081413͔The key factor improving the performances of thin film devices based on organic semiconductors is the achievement of high charge mobility through the control of growth mechanisms aimed at improving the structural quality and morphology of the thin films. 1 The fine tuning of the material properties by a suitable modification of the molecular orientation and packing ͑crucial for determining the electronic band structure of the solid film and its charge-transport properties͒ 2 represents an alternative experimental opportunity. The arrangement of different organic semiconductors in multilayer architectures, including semiconductor junctions, gives further beneficial effects in thin film devices. 1 In this framework, organic molecular beam epitaxy ͑OMBE͒ represents the best choice among the growth techniques, assuring high quality films and controlled interfaces in organic heterostructures in view of both fundamental studies and applications. 3,4 Among the strategies for growing samples with designed properties, one of the most promising is the use of organic substrates 5-7 whose effect in tuning the molecular orientation of the overlayer has been already demonstrated. In particular, when organic single crystals are used as substrates, highly oriented organic heterostructures are grown even in the absence of any geometric coincidence between substrate and overlayer ͑incommensurate epitaxy͒. 5,[8][9][10][11][12][13] In this letter, we investigate the properties of an organic-organic heterostructure by demonstrating the OMBE growth of an epitaxial pseudomorphic phase of the ␣-quaterthiophene ͑␣-4T͒ film on tetracene ͑TEN͒ single crystals. By means of reflectance anisotropy spectroscopy ͑RAS͒, we monitored in situ the OMBE process, showing that the ␣-4T overlayer grows with a distorted lattice structure with respect to the bulk crystal, which results in incommensurate epitaxy. In addition, the full ex situ stability of this new phase is demonstrated so that organic-organic epitaxy is definitely assessed as a powerful tool for tuning the properties of the growing films. 14 ␣-4T was synthesized and purified according to Ref. 15, while commercial TEN was purified by several sublimation steps before use. TEN single crystals were grown by physical vapor transport. 16 Its crystal structure belongs to the triclinic system, with unit cell parameters a = 6.06 Å, b = 7.84 Å, c = 13.01 Å, ␣ = 77.13°, ␤ = 72.12°, ␥ = 85.79...

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“…The technique itself was introduced in the mid 1980s [5][6][7] and is nowadays used in both surface science and in semiconductor technology ͓as growth control in gaseous environments, such as in metal organic vapor phase epitaxy ͑MOVPE͒, where electron based methods cannot be applied 8,9 ͔. The origin of the RAS response from anisotropic surfaces is quite well understood and can be calculated ab initio within density functional based theories.…”

Section: Introductionmentioning

confidence: 99%

Free-electron response in reflectance anisotropy spectra

et al. 2006

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Reflectance anisotropy spectra ͑RAS͒, extended into the near infrared spectral region, of anisotropic metal islands, metal surfaces, and atomic nanowires are analyzed with respect to anisotropies in the optical response of the free-electron gas of such low dimensional metal structures. In order to distinguish conductivity and morphology effects, both a phenomenological anisotropic Drude model and an effective medium model using ellipsoidal metal inclusions are used to model the spectra. In some cases ͑metal islands͒ the RAS response is dominated by the free-electron contribution, while this contribution is significantly smaller for the metal surfaces and nanowires in the accessible spectral range.

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Epitaxy

Cited by 133 publications

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Van der Waals solid phase epitaxy to grow large-area manganese-doped MoSe ₂ few-layers on SiO ₂ /Si

Van der Waals solid phase epitaxy to grow large-area manganese-doped MoSe ₂ few-layers on SiO ₂ /Si

Pseudomorphic growth of organic semiconductor thin films driven by incommensurate epitaxy

Free-electron response in reflectance anisotropy spectra

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Epitaxy

Cited by 133 publications

References 0 publications

Van der Waals solid phase epitaxy to grow large-area manganese-doped MoSe 2 few-layers on SiO 2 /Si

Van der Waals solid phase epitaxy to grow large-area manganese-doped MoSe 2 few-layers on SiO 2 /Si

Pseudomorphic growth of organic semiconductor thin films driven by incommensurate epitaxy

Free-electron response in reflectance anisotropy spectra

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Van der Waals solid phase epitaxy to grow large-area manganese-doped MoSe ₂ few-layers on SiO ₂ /Si

Van der Waals solid phase epitaxy to grow large-area manganese-doped MoSe ₂ few-layers on SiO ₂ /Si