STM-Induced Hydrogen Desorption via a Hole Resonance

Abstract

We report STM-induced desorption of H from Si(100)-H(2×1) at negative sample bias. The desorption rate exhibits a power-law dependence on current and a maximum desorption rate at −7 V. The desorption is explained by vibrational heating of H due to inelastic scattering of tunneling holes with the Si-H 5σ hole resonance. The dependence of desorption rate on current and bias is analyzed using a novel approach for calculating inelastic scattering, which includes the effect of the electric field between tip and sample. We show that the maximum desorption rate at −7 V is due to a maximum fraction of inelastically scattered electrons at the onset of the field emission regime.

Visible Light Emission from Atomic Scale Patterns Fabricated by the Scanning Tunneling Microscope

“…0 or a hole for V b , 0 after tunneling through the tip-surface barrier causes an optical transition in the semiconductor via a dangling bond channel. At negative bias, only a small fraction of the hole current originates from low lying hole states [7], and in contrast to the experimental observations, QE would be much lower for V b , 0 than for V b . 0.…”

“…1(B) was recorded at negative V b ; but for positive V b , H desorption occurs at a much lower I t [2,7] where I photon would be too low to be detected with the present system. However, the desorption yield of deuterium (D) from D-terminated Si(001) surfaces is much lower than the corresponding desorption yield of H [8].…”

Electric field dependent structural and vibrational properties of the Si(100)-H(2×1) surface and its implications for STM induced hydrogen desorption

“…At high positive biases, V b > 4 V, the experimental results are consistent with electron induced desorption due to direct excitation of the Si-H bond by a single electron [4][5][6]. At negative and low positive biases the desorption rates show powerlaw dependencies on the electron current [4,11] consistent with a multi-electron process [4,14,15], and the measured desorption rates are in quantitative agreement with firstprinciple calculations [11,12].…”

Theories of scanning probe microscopes at the atomic scale

“…These effects have been analyzed by theoretical models of scanning tunneling microscopy in various instances: (i) the effect of the tip potential on semiconductor surfaces with an adsorbed organic molecule like acetylene Fisher, 1997a, 1997b;Stokbro et al, 1998); (ii) the effect of the tip potential on the electronic structure of metal surfaces ; and (iii) the effect of electrostatic fields on the structure of sample and tip in a continuum model (Hansen et al, 1998). In the first case the effect leads to a change of the tip-sample distance of about 0.1 at 6 Å.…”