Comparison of hydrogen desorption kinetics from Si(111)7 × 7 and Si(100)2 × 1

Wise, Michael L.; Koehler, Birgit; Gupta, Pawan; Coon, P. A.; George, Steven M.

doi:10.1016/0039-6028(91)90911-b

Cited by 281 publications

(63 citation statements)

References 31 publications

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“…The nearly constant peak temperatures, Tp, together with the asymmetric peak shape at high initial coverage, indicate near first-order desorption kinetics [9]. However, the slight increase in Tp and the more symmetric peak shape at lower initial coverages demonstrate a slight departure from first-order kinetics, as also occurs for hydrogen on Si(100) [10][11][12]. The dependence of Tp on 0 is shown in Fig.…”

Section: Resultsmentioning

confidence: 83%

Hydrogen-halogen chemistry on semiconductor surfaces

et al. 1993

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Section: Resultsmentioning

confidence: 83%

Hydrogen-halogen chemistry on semiconductor surfaces

et al. 1993

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“…For this surface, experiments have shown that desorption obeys an approximately second-order kinetics with an activation barrier of ~ 2.5 eV [17][18][19][20]. As for Si(100)-(2 x 1), sticking-coefficient measurements have shown that adsorption is activated with an effective barrier of 0.87 +0.1 eV [21].…”

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confidence: 99%

H2 adsorption/desorption at Si(111)-(7 × 7): a density functional study

Vittadini

Selloni

1997

Surface Science

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The interaction of H 2 with the Si( 111 )-(7 x 7) surface is investigated by means of density functional slab calculations on a (4 x 2) reconstructed model surface. A viable mechanism for fll desorption is identified, which involves thermally activated Sill 2 units at adatom sites. This mechanism leads to adsorption and desorption barriers of 1.0 and 2.4 eV, respectively, in agreement with experiment. An explanation for the two components observed in the ~ peak of temperature-programmed desorption spectra is proposed. The lattice deformation energy at the transition state for desorption is large (~ 0.6 eV ). If we assume that this remains in the surface after H 2 desorption, the low translational energy of desorbing molecules which has been observed experimentally can in part be explained. © 1997 Elsevier Science B.V.

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“…that the first-order kinetics results from the rate-limiting excitation of hydrogen atoms to a band-like delocalized state 1 was contradicted by the near-second-order kinetics observed for desorption of hydrogen from Si( 11),2-4 by measurements of the diffusion kinetics of hydrogen on Si(l 11) which suggest conventional hopping, 5 and by dynamical measurements showing that desorbing H 2 is rotationally cold and vibrationally hot, implying a highly symmetric transition state. 6 Wise et al 2 suggested that the desorption kinetics are first order due instead to pairing of hydrogen on the dimerized surface atoms, and Boland 7 and we 8 independently proposed that preferential pairing of H atoms is a consequence of the ic bond 9 , 10 on "unoccupied" dimers. Boland obtained direct evidence for preferential pairing by scanning tunneling microscopy (STM) and estimated a a bond strength of =18 kcal/mol from tunneling spectra above un-and singly-occupied dimers.…”

Section: Submitted To Journal Of Vacuum Science and Technology A Intrmentioning

confidence: 78%

“…14 The adsorbate-ordering portion of this model is precisely a one-dimensional lattice gas model with nearest neighbor interactions whose solution has been described by Hill. 16 Defining e9 and a as the surface hydrogen coverage and the fraction of "bonds" between adjacent dimers where one of the dimers is (doubly) occupied and the other is unoccupied, the solution to the mximization condition for the partition function can be written as 16 a 2 (2) (e-a) (1-e-a)…”

Section: Generalized Model and Theoretical Methodsmentioning

confidence: 99%

“…The discovery by Sinniah et al that recombinative hydrogen desorption follows firstorder kinetics on Si(100)2xl,1 in contrast to the second-order behavior seen on metal surfaces, has prompted a great deal of recent work on the kinetics and dynamics of hydrogen desorption, including verification by George and co-workers. 2 The original proposal by Sinniah et al. that the first-order kinetics results from the rate-limiting excitation of hydrogen atoms to a band-like delocalized state 1 was contradicted by the near-second-order kinetics observed for desorption of hydrogen from Si( 11),2-4 by measurements of the diffusion kinetics of hydrogen on Si(l 11) which suggest conventional hopping, 5 and by dynamical measurements showing that desorbing H 2 is rotationally cold and vibrationally hot, implying a highly symmetric transition state.…”

Section: Submitted To Journal Of Vacuum Science and Technology A Intrmentioning

confidence: 99%

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Pairing and clustering of hydrogen on Si(100)2×1: Monte Carlo studies

Yang

D'Evelyn

1993

Journal of Vacuum Science &Amp; Technology A: Vacuum, Surfaces, and Films

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Pubihc reocrtinrg ourcden fr this ccilecion of information is eitimated to average 1 hour opr reponse. including the time for revewing instruclons. searching extng data wOur(es gather~r'q and rraonta.ng the data needed, and completing and rev eving the ýollectlon of information Send comments regarding this burden estimate Or any other aspect of this colle-mton of ntormaton. nclud ng suggestons for reducing this iourden. to Washington readcltuarters Servies. Directorate for information Operations and Reports. Approved for public release; distribution is unlimited. ABSTRACT (Maximum 200 words)We consider a generalization of the doubly-occupied dimer model we proposed recently to explain the near-first-order desorption kinetics of H2 from Si(100)2xl, incorporating effective nearest-neighbor interactions between paired hydrogen atoms on adjacent dimers. We have performed Monte Carlo simulations of the generalized model, and compare the pairing and cluster-size distributions with those observed recently by scanning tunneling microscopy (STM). The agreement is reasonable but the cluster size distributions differ in shape, which we suggest is due to the nonthermal nature of the distributions observed by STM and/or inadequacies in the use of nearest-neighbor interactions to represent the physics of clustering.Implications of the results for the underlying physical interactions responsible for ordering of hydrogen on Si(100) and for the desorption kinetics are discussed.14. Prexrfbed by ANSI Std Z39-18 296-102Pairing and clustering of hydrogen on Si (100)

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Comparison of hydrogen desorption kinetics from Si(111)7 × 7 and Si(100)2 × 1

Cited by 281 publications

References 31 publications

Hydrogen-halogen chemistry on semiconductor surfaces

Hydrogen-halogen chemistry on semiconductor surfaces

H2 adsorption/desorption at Si(111)-(7 × 7): a density functional study

Pairing and clustering of hydrogen on Si(100)2×1: Monte Carlo studies

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