Carbon incorporation in MOCVD of MoS2 thin films grown from an organosulfide precursor
Schaefer, Christian M. (Institut Català de Nanociència i Nanotecnologia)
Caicedo Roque, Jose Manuel (Institut Català de Nanociència i Nanotecnologia)
Sauthier, Guillaume (Institut Català de Nanociència i Nanotecnologia)
Bousquet, Jessica (Institut Català de Nanociència i Nanotecnologia)
Hébert, Clément (Institut Català de Nanociència i Nanotecnologia)
Sperling, Justin R. (Institut Català de Nanociència i Nanotecnologia)
Perez-Tomas, Amador (Institut Català de Nanociència i Nanotecnologia)
Santiso, José (Institut Català de Nanociència i Nanotecnologia)
Del Corro, Elena (Institut Català de Nanociència i Nanotecnologia)
Garrido, Jose (Institut Català de Nanociència i Nanotecnologia)

Fecha:	2021
Resumen:	With the rise of two-dimensional (2D) transition-metal dichalcogenide (TMD) semiconductors and their prospective use in commercial (opto)electronic applications, it has become key to develop scalable and reliable TMD synthesis methods with well-monitored and controlled levels of impurities. While metal-organic chemical vapor deposition (MOCVD) has emerged as the method of choice for large-scale TMD fabrication, carbon (C) incorporation arising during MOCVD growth of TMDs has been a persistent concern-especially in instances where organic chalcogen precursors are desired as a less hazardous alternative to more toxic chalcogen hydrides. However, the underlying mechanisms of such unintentional C incorporation and the effects on film growth and properties are still elusive. Here, we report on the role of C-containing side products of organosulfur precursor pyrolysis in MoS2 thin films grown from molybdenum hexacarbonyl Mo(CO)6 and diethyl sulfide (CH3CH2)2S (DES). By combining in situ gas-phase monitoring with ex situ microscopy and spectroscopy analyses, we systematically investigate the effect of temperature and Mo(CO)6/DES/H2 gas mixture ratios on film morphology, chemical composition, and stoichiometry. Aiming at high-quality TMD growth that typically requires elevated growth temperatures and high DES/Mo(CO)6 precursor ratios, we observed that temperatures above DES pyrolysis onset (â 600 °C) and excessive DES flow result in the formation of nanographitic carbon, competing with MoS2 growth. We found that by introducing H2 gas to the process, DES pyrolysis is significantly hindered, which reduces carbon incorporation. The C content in the MoS2 films is shown to quench the MoS2 photoluminescence and influence the trion-To-exciton ratio via charge transfer. This finding is fundamental for understanding process-induced C impurity doping in MOCVD-grown 2D semiconductors and might have important implications for the functionality and performance of (opto)electronic devices.
Ayudas:	European Commission 732032 European Commission 825430 European Commission 881603 Agència de Gestió d'Ajuts Universitaris i de Recerca 2017/SGR-1426 Agencia Estatal de Investigación FIS2017-85787-R Agencia Estatal de Investigación SEV-2017-0706
Nota:	Altres ajuts: CERCA Programme/Generalitat de Catalunya
Derechos:	Tots els drets reservats.
Lengua:	Anglès
Documento:	Article ; recerca ; Versió acceptada per publicar
Materia:	A3. metal organic chemical vapor deposition (MOCVD) ; Chemical compositions ; Effect of temperature ; Electronic application ; Molybdenum hexacarbonyl ; Nanographitic carbons ; Transition metal dichalcogenides ; Two Dimensional (2 D)
Publicado en:	Chemistry of materials, Vol. 33, Issue 12 (June 2021) , p. 4474-4487, ISSN 1520-5002

DOI: 10.1021/acs.chemmater.1c00646

Postprint 18 p, 1.4 MB

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Documentos de investigación > Documentos de los grupos de investigación de la UAB > Centros y grupos de investigación (producción científica) > Ciencias > Institut Català de Nanociència i Nanotecnologia (ICN2)
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