75 research outputs found
Silicon Sheets By Redox Assisted Chemical Exfoliation
In this paper, we report the direct chemical synthesis of silicon sheets in
gram-scale quantities by chemical exfoliation of pre-processed calcium
di-silicide (CaSi2). We have used a combination of X-ray photoelectron
spectroscopy, transmission electron microscopy and Energy-dispersive X-ray
spectroscopy to characterize the obtained silicon sheets. We found that the
clean and crystalline silicon sheets show a 2-dimensional hexagonal graphitic
structure.Comment: Accepted in J. Phys.: Condens. Matte
Growth and reactivity of silicene
Lâobjet de cette thĂšse est lâĂ©tude de la croissance de silicĂšne sur des substrats dâargent,ainsi que lâĂ©tude de sa rĂ©activitĂ© vis-Ă -vis de lâoxygĂšne. La croissance a Ă©tĂ© rĂ©alisĂ©e sous ultra-vide et contrĂŽlĂ©e par spectroscopie dâĂ©lectrons Auger (AES) et par diffraction dâĂ©lectrons lents (LEED). Les structures obtenues et leurs rĂ©activitĂ©s Ă lâoxygĂšne ont Ă©tĂ© Ă©tudiĂ©es par microscopie Ă champ proche (STM et nc-AFM) et par spectroscopie de photoĂ©mission rĂ©solue en angle (ARPES). Nous avons Ă©tudiĂ© la structure interne des nano-rubans de silicĂšne auto-assemblĂ©s sur un substrat dâAg(110). Sur Ag(111) nous obtenons un feuillet de silicĂšne qui prĂ©sente diffĂ©rentes structures en fonction de la tempĂ©rature du substrat. LâĂ©tude de la rĂ©activitĂ© des rubans et des feuillets a montrĂ© que le silicĂšne formĂ© sur substrat dâargent est relativement stable vis-Ă -vis de lâoxygĂšne ce qui ouvre des perspectives de fonctionnalisation du silicĂšne. La derniĂšre partie de cette thĂšse concerne la synthĂšse de feuillets de silicium par voie chimique. Nous avons mis au point une nouvelle mĂ©thode prometteuse de synthĂšse chimique qui nous a permis de synthĂ©tiser des feuillets de silicium de structure graphitique.The objective of this thesis is the study of the growth of silicene on silver substrates as well as its reactivity towards the oxygen. The growth was performed under ultra-high vacuum and controlled by Auger electrons spectroscopy (AES) and low energy electrons diffraction (LEED). The obtained structures and their relativities towards the oxygen were studied by near field microscopy (STM and nc-AFM) and by angle resolved electrons photoemission spectroscopy (ARPES). We have studied the internal structure of the selfassembled silicene nanoribbons on Ag(110) substrate. On Ag(111), we have obtained a silicene sheet presenting different structures versus the temperature of the substrate. The reactivity of silicene nanoribbons and sheets grown on silver show that silicene is relatively stable towards the oxygen which opens a new perspectives of functionalization of the silicene. The last part of this thesis concerns the synthesis of silicone sheets by chemical process. We have develpped a new promising process of chemical synthesis which allowed us to synthesize silicon sheets with graphitic structure
Croissance et réactivité du silicÚne
The objective of this thesis is the study of the growth of silicene on silver substrates as well as its reactivity towards the oxygen. The growth was performed under ultra-high vacuum and controlled by Auger electrons spectroscopy (AES) and low energy electrons diffraction (LEED). The obtained structures and their relativities towards the oxygen were studied by near field microscopy (STM and nc-AFM) and by angle resolved electrons photoemission spectroscopy (ARPES). We have studied the internal structure of the selfassembled silicene nanoribbons on Ag(110) substrate. On Ag(111), we have obtained a silicene sheet presenting different structures versus the temperature of the substrate. The reactivity of silicene nanoribbons and sheets grown on silver show that silicene is relatively stable towards the oxygen which opens a new perspectives of functionalization of the silicene. The last part of this thesis concerns the synthesis of silicone sheets by chemical process. We have develpped a new promising process of chemical synthesis which allowed us to synthesize silicon sheets with graphitic structure.Lâobjet de cette thĂšse est lâĂ©tude de la croissance de silicĂšne sur des substrats dâargent,ainsi que lâĂ©tude de sa rĂ©activitĂ© vis-Ă -vis de lâoxygĂšne. La croissance a Ă©tĂ© rĂ©alisĂ©e sous ultra-vide et contrĂŽlĂ©e par spectroscopie dâĂ©lectrons Auger (AES) et par diffraction dâĂ©lectrons lents (LEED). Les structures obtenues et leurs rĂ©activitĂ©s Ă lâoxygĂšne ont Ă©tĂ© Ă©tudiĂ©es par microscopie Ă champ proche (STM et nc-AFM) et par spectroscopie de photoĂ©mission rĂ©solue en angle (ARPES). Nous avons Ă©tudiĂ© la structure interne des nano-rubans de silicĂšne auto-assemblĂ©s sur un substrat dâAg(110). Sur Ag(111) nous obtenons un feuillet de silicĂšne qui prĂ©sente diffĂ©rentes structures en fonction de la tempĂ©rature du substrat. LâĂ©tude de la rĂ©activitĂ© des rubans et des feuillets a montrĂ© que le silicĂšne formĂ© sur substrat dâargent est relativement stable vis-Ă -vis de lâoxygĂšne ce qui ouvre des perspectives de fonctionnalisation du silicĂšne. La derniĂšre partie de cette thĂšse concerne la synthĂšse de feuillets de silicium par voie chimique. Nous avons mis au point une nouvelle mĂ©thode prometteuse de synthĂšse chimique qui nous a permis de synthĂ©tiser des feuillets de silicium de structure graphitique
Croissance et réactivité du silicÚne
The objective of this thesis is the study of the growth of silicene on silver substrates as well as its reactivity towards the oxygen. The growth was performed under ultra-high vacuum and controlled by Auger electrons spectroscopy (AES) and low energy electrons diffraction (LEED). The obtained structures and their relativities towards the oxygen were studied by near field microscopy (STM and nc-AFM) and by angle resolved electrons photoemission spectroscopy (ARPES). We have studied the internal structure of the selfassembled silicene nanoribbons on Ag(110) substrate. On Ag(111), we have obtained a silicene sheet presenting different structures versus the temperature of the substrate. The reactivity of silicene nanoribbons and sheets grown on silver show that silicene is relatively stable towards the oxygen which opens a new perspectives of functionalization of the silicene. The last part of this thesis concerns the synthesis of silicone sheets by chemical process. We have develpped a new promising process of chemical synthesis which allowed us to synthesize silicon sheets with graphitic structure.Lâobjet de cette thĂšse est lâĂ©tude de la croissance de silicĂšne sur des substrats dâargent,ainsi que lâĂ©tude de sa rĂ©activitĂ© vis-Ă -vis de lâoxygĂšne. La croissance a Ă©tĂ© rĂ©alisĂ©e sous ultra-vide et contrĂŽlĂ©e par spectroscopie dâĂ©lectrons Auger (AES) et par diffraction dâĂ©lectrons lents (LEED). Les structures obtenues et leurs rĂ©activitĂ©s Ă lâoxygĂšne ont Ă©tĂ© Ă©tudiĂ©es par microscopie Ă champ proche (STM et nc-AFM) et par spectroscopie de photoĂ©mission rĂ©solue en angle (ARPES). Nous avons Ă©tudiĂ© la structure interne des nano-rubans de silicĂšne auto-assemblĂ©s sur un substrat dâAg(110). Sur Ag(111) nous obtenons un feuillet de silicĂšne qui prĂ©sente diffĂ©rentes structures en fonction de la tempĂ©rature du substrat. LâĂ©tude de la rĂ©activitĂ© des rubans et des feuillets a montrĂ© que le silicĂšne formĂ© sur substrat dâargent est relativement stable vis-Ă -vis de lâoxygĂšne ce qui ouvre des perspectives de fonctionnalisation du silicĂšne. La derniĂšre partie de cette thĂšse concerne la synthĂšse de feuillets de silicium par voie chimique. Nous avons mis au point une nouvelle mĂ©thode prometteuse de synthĂšse chimique qui nous a permis de synthĂ©tiser des feuillets de silicium de structure graphitique
Atomic Structure Of Silicene Nanoribbons On Ag(110)
The growth of silicene nano-ribbons (NRs) on Ag(110) substrate is re-investigated using scanning tunneling microscopy (STM) and low energy electron diffraction (LEED). Deposition of one silicon monolayer at 230°C induces the formation of one-dimensional 1.6 nm wide silicene nanoribbons into a well-ordered compact array with a nanometer-scale pitch of just 2 nm. Based on the STM analysis we derived an atomic model of the silicene nanoribbons (NRs) where they are substantially buckled, and quantum confinement of the electrons in the NRs contribute to electronic density of states. © Published under licence by IOP Publishing Ltd
Combined Afm And Stm Measurements Of A Silicene Sheet Grown On The Ag(111) Surface
In this paper, we present the first non-contact atomic force microscopy (nc-AFM) of a silicene on a silver (Ag) surface, obtained by combining non-contact atomic force microscopy and scanning tunneling microscopy (STM). STM images over large areas of silicene grown on the Ag(111) surface show both (â13 Ă â13)R13.9° and (4 Ă 4) superstructures. For the widely observed (4 Ă 4) structure, the observed nc-AFM image is very similar to the one recorded by STM. The structure resolved by nc-AFM is compatible with only one out of two silicon atoms being visible. This indicates unambiguously a strong buckling of the silicene honeycomb layer. © 2013 IOP Publishing Ltd
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