Ultraviolet photoemission spectroscopy of HCl on Si(111) surfaces

Chemisorption of HCl on thermally cleaned Si(111) surfaces has been studied by ultraviolet photoemission spectroscopy. HCl chemisorption, both at 300K and 850 K, induces two main peaks in the photoemission spectrum which are attributed to Cl lone pair p_x, p_y orbitals and Si: sp³?Cl:p_z bonding orbital, respectively. This strongly suggests that HCl molecules dissociate on Si(111) surfaces already at room temperature.