STM-induced H atom desorption from Si(100): isotope effects and site selectivity

Avouris, Phaedon; Walkup, R. E.; Rossi, Angelo R.; Shen, T. C.; Abeln, G. C.; Tucker, J. R.; Lyding, Joseph W.

doi:10.1016/0009-2614(96)00518-0

Cited by 172 publications

(70 citation statements)

References 17 publications

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“…7,19 Only a few works have treated different atomic potential energy surfaces (PES) other than the truncated harmonic. Avouris et al 23 used atomic wave-packet propagations to evaluate the atomic dynamics in an excited PES after electron tunneling. More recently, the anharmonicity of the PES as revealed by density functional theory (DFT) was used to explain the electron induced motion of ammonia molecules on Cu(100).…”

Section: Introductionmentioning

confidence: 99%

Tunneling electron induced rotation of a copper phthalocyanine molecule on Cu(111)

et al. 2013

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The rates of a hindered molecular rotation induced by tunneling electrons are evaluated using scattering theory within the sudden approximation. Our approach explains the excitation of copper phthalocyanine molecules (CuPc) on Cu(111) as revealed in a recent measurement of telegraph noise in a scanning tunneling microscopy experiment [Schaffert et al., Nat. Mater. 12, 223 (2013)]. A complete explanation of the experimental data is performed by computing the geometry of the adsorbed system, its electronic structure, and the energy transfer between tunneling electrons and the molecule's rotational degree of freedom. The results unambiguously show that tunneling electrons induce a frustrated rotation of the molecule. In addition, the theory determines the spatial distribution of the frustrated rotation excitation, confirming the striking dominance of two out of four molecular lobes in the observed excitation process. This lobe selectivity is attributed to the different hybridizations with the underlying substrate.

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Section: Introductionmentioning

confidence: 99%

Tunneling electron induced rotation of a copper phthalocyanine molecule on Cu(111)

et al. 2013

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“…9,15,16 The desorption of atoms from surfaces can be induced by electronic excitations directly by coupling between the laser field and the bond electrons or by indirect mechanisms where the excitation of the substrate is transferred to the desorption coordinates. 7,17,18 Ab initio approaches have been very successful in describing the physical properties of hydrogenated Si surfaces. [19][20][21][22][23][24] These studies have revealed the surface relaxation mechanisms, 19,21 surface atom vibrational modes, 20,22 phonon-phonon interactions, 25 and other structural and energetic properties.…”

Section: Introductionmentioning

confidence: 99%

Electron-ion dynamics in laser-assisted desorption of hydrogen atoms from H-Si(111) surface

Bubin

Varga

2011

Journal of Applied Physics

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In the framework of real time real space time-dependent density functional theory we have studied the electron-ion dynamics of a hydrogen-terminated silicon surface H-Si(111) subjected to intense laser irradiation. Two surface fragments of different sizes have been used in the simulations. When the intensity and duration of the laser exceed certain levels (which depend on the wavelength) we observe the desorption of the hydrogen atoms, while the underlying silicon layer remains essentially undamaged. Upon further increase of the laser intensity, the chemical bonds between silicon atoms break as well. The results of the simulations suggest that with an appropriate choice of laser parameters it should be possible to remove the hydrogen layer from the H-Si(111) surface in a matter of a few tens of femtoseconds. We have also observed that at high laser field intensities (2-4 V=Å in this work) the desorption occurs even when the laser frequency is smaller than the optical gap of the silicon surface fragments. Therefore, nonlinear phenomena must play an essential role in such desorption processes.

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“…[6][7][8][9] Desorption of atoms from surfaces can be induced by electronic excitations directly by coupling between the laser field and the bond electrons or by indirect mechanisms, where the excitation of the substrate transferred to the desorption coordinates. [10][11][12] Desorption of atoms can also be initiated by other forms of energy transfer to the system, e.g., by moving a scanning tunneling microscope ͑STM͒ tip close to the surface. 10,13 The hydrogen-terminated Si͑111͒ surface is one of the simplest and basic examples of a semiconductor interface.…”

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First-principles time-dependent simulation of laser assisted desorption of hydrogen atoms from H–Si(111) surface

Bubin

Varga

2011

Applied Physics Letters

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The dynamics of hydrogen desorption from H-terminated silicon surface clusters has been simulated in the framework of real space time-dependent density functional theory complemented with molecular dynamics for ions. It has been demonstrated that by choosing an appropriate frequency and intensity of the laser it is possible to remove the hydrogen layer from the surface without destroying the structure of underlying silicon. At the laser field intensities used in the current study ͑0.5-2.0 V/Å͒ the desorption process is notably nonlinear. © 2011 American Institute of Physics. ͓doi:10.1063/1.3580563͔Bond scission by laser pulses is an ideal way to induce and control chemical reactions. [1][2][3][4] Selective control of surface reactions 4 is especially desired as it allows patterning of reaction areas by creating dangling bonds and fabricating functionalized structures by active manipulation of chemical bonds. 5 Among the many surfaces explored by experiments, the hydrogen terminated Si surface is the most studied system. [6][7][8][9] Desorption of atoms from surfaces can be induced by electronic excitations directly by coupling between the laser field and the bond electrons or by indirect mechanisms, where the excitation of the substrate transferred to the desorption coordinates. [10][11][12] Desorption of atoms can also be initiated by other forms of energy transfer to the system, e.g., by moving a scanning tunneling microscope ͑STM͒ tip close to the surface. 10,13 The hydrogen-terminated Si͑111͒ surface is one of the simplest and basic examples of a semiconductor interface. Hydrogen atoms chemisorbed onto dangling bonds of the silicon substrate form a protection layer that prevents oxidation and adsorption of impurities. In spite of its apparent simplicity, the hydrogenation of H-Si͑111͒ surface is important for both industrial applications and understanding of fundamental processes and mechanisms, including those that occur in more complicated systems.In this letter, we will carry out first-principles timedependent simulations of laser assisted hydrogen desorption from a Si͑111͒ surface. The physical mechanisms behind the laser induced desorption are not fully understood and computer simulations are indispensable to gain physical insights of the problem. The real space real time density functional calculation complemented with Ehrenfest molecular dynamics simulation presented in this letter shows that the hydrogen layer can be removed from a silicon surface with a proper choice of laser parameters. This process, which does not destroy the underlying silicon surface, is highly nonequilibrium and nonlinear. The results of the study enhance our understanding of the dynamics of electrons and atoms in and on surfaces.Hydrogen desorption from silicon has been subject to various theoretical studies 14-18 including first-principles time-dependent simulations. 19 The latter work simulated the STM induced desorption: The Si-H bond of the hydrogenated S͑111͒ surface was subjected an excitation by promoting electrons from...

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STM-induced H atom desorption from Si(100): isotope effects and site selectivity

Cited by 172 publications

References 17 publications

Tunneling electron induced rotation of a copper phthalocyanine molecule on Cu(111)

Tunneling electron induced rotation of a copper phthalocyanine molecule on Cu(111)

Electron-ion dynamics in laser-assisted desorption of hydrogen atoms from H-Si(111) surface

First-principles time-dependent simulation of laser assisted desorption of hydrogen atoms from H–Si(111) surface

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