Strain Activation of Surface Chemistry on H-Terminated Si(111)

Abstract

Manipulation of the chemical and electronic properties of materials by strain is a widely accepted phenomenon. However, the impact of strain on microscopic aspects such as chemical reactivity is not clearly understood at the bond level. Here, we investigated the effect of strain on surface reactivity of H–Si(111). Analysis of FTIR data revealed that a decrease in stretching Si–H band’s intensity and fluctuations in intensity of the bending Si–H mode, which are in relation to the appearance of a new peak, are correlated with each other. The underlying reason for the new peak is the formation of a three-center bond as a result of diffusion of a hydrogen atom from the Si–H site. Our findings show that both the back bonds and the up bonds are easily oxidized due to the strain effect. In particular, the significant point is direct formation of Si–OH without any energy barrier. As strain is applied to the samples, the findings indicate that different oxidation pathways predominate.