Temperature suppression of STM-induced desorption of hydrogen on Si(100) surfaces

TL;DR

This study investigates how increasing temperature suppresses hydrogen desorption from Si(100) surfaces induced by STM, revealing a strong bias-dependent effect explained by vibrational heating and hole resonance lifetime.

Contribution

It provides the first detailed analysis of temperature effects on STM-induced hydrogen desorption, linking suppression to vibrational heating and hole resonance dynamics.

Findings

Desorption rate decreases significantly with temperature increase.

Suppression is highly bias-dependent, more at -7 V than -5 V.

Vibrational heating and hole resonance lifetime explain the temperature dependence.

Abstract

The temperature dependence of hydrogen (H) desorption from Si(100) H-terminated surfaces by a scanning tunneling microscope (STM) is reported for negative sample bias. It is found that the STM induced H desorption rate ($R$) decreases several orders of magnitude when the substrate temperature is increased from 300 K to 610 K. This is most noticeable at a bias voltage of -7 V where $R$ decreases by a factor of ~200 for a temperature change of 80 K, whilst it only decreases by a factor of ~3 at -5 V upon the same temperature change. The experimental data can be explained by desorption due to vibrational heating by inelastic scattering via a hole resonance. This theory predicts a weak suppression of desorption with increasing temperature due to a decreasing vibrational lifetime, and a strong bias dependent suppression due to a temperature dependent lifetime of the hole resonance.