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

Abstract We investigate the scanning tunnelling microscopy-induced H and D atom desorption from Si(100)-(2 × 1):H(D). The desorption of both atoms shows the same energy threshold that corresponds well with the computed σ → σ ∗ excitation energy of the SiH group. The H desorption yield, however, is much higher than the D yield. We ascribe this to the greater influence of quenching processes on the excited state of the SiD species. We use wavepacket dynamics to follow the motion of H and D atoms, and conclude that desorption occurs, for the most part, from the ‘hot’ ground state populated by the quenching process. Site-selective excitation-induced chemistry is found in the desorption of H from Si(100)-(3 × 1):H.

[1]  R. Street,et al.  Hydrogenated amorphous silicon: Index , 1991 .

[2]  R. Walkup.  A local‐Gaussian approximation for the propagation of a classical distribution function , 1991 .

[3]  Peter Nordlander,et al.  Breaking individual chemical bonds via STM-induced excitations , 1996 .

[4]  B. Meyerson,et al.  Mechanistic Studies of Chemical Vapor Deposition , 1987 .

[5]  Robert E. Walkup,et al.  Fundamental Mechanisms of Desorption and Fragmentation Induced by Electronic Transitions at Surfaces , 1989 .

[6]  P. Avouris,et al.  Scanning tunneling microscopy (STM) studies of the chemical vapor deposition of Ge on Si(111) from Ge hydrides and a comparison with molecular beam epitaxy , 1994 .

[7]  H. Iwasaki,et al.  Electronic structures of the monohydride (2×1):H and the dihydride (1×1)𕘨H Si(001) surfaces studied by angle-resolved electron-energy-loss spectroscopy , 1983 .

[8]  Becker,et al.  Atomic-scale conversion of clean Si(111):H-1 x 1 to Si(111)-2 x 1 by electron-stimulated desorption. , 1990, Physical review letters.

[9]  J R Tucker,et al.  Atomic-Scale Desorption Through Electronic and Vibrational Excitation Mechanisms , 1995, Science.

[10]  K. Jordan,et al.  Theoretical study of the mechanism of recombinative hydrogen desorption from the monohydride phase of Si(100): The role of defect migration , 1994 .

[11]  P. Avouris,et al.  The effects of the electric field in the STM on excitation localization. Implications for local bond breaking , 1995 .

[12]  Dumas,et al.  Lifetime of an adsorbate-substrate vibration: H on Si(111). , 1990, Physical review letters.

[13]  J. Boland.  Scanning tunnelling microscopy of the interaction of hydrogen with silicon surfaces , 1993 .

[14]  P. Guyot-Sionnest,et al.  Vibrational dynamics of the Si–H stretching modes of the Si(100)/H:2×1 surface , 1995 .

[15]  Phaedon Avouris,et al.  Atom-resolved surface chemistry using the scanning tunneling microscope , 1990 .

[16]  Raghavachari,et al.  New ordered structure for the H-saturated Si(100) surface: The (3 x 1) phase. , 1985, Physical review letters.