Interaction of 2-Propanol with the GaAs(100) Surface

Abstract

Synchrotron photoemission spectroscopy is applied to study the interaction of 2-propanol with the clean GaAs(100) surface to understand the solid−solvent interaction at the semiconductor/electrolyte interface. Adsorption of 2-propanol molecules at liquid-nitrogen temperature and emersion of the semiconductor from liquid 2-propanol at room temperature are performed to gain a more detailed insight into surface reaction steps and processes involved. It is found that on adsorption at liquid-nitrogen temperature a 2-propanol molecule dissociates on a GaAs(100) surface to a hydrogen atom, which is adsorbed on an As atom that is part of an As−As dimer, and a 2-propoxy group, which adsorbs to an adjacent Ga atom. On a GaAs(100) surface emersed from liquid 2-propanol at room temperature, two different states of dissociative adsorption are observed. The first state corresponds to dissociation of a 2-propanol molecule into a hydrogen atom and a 2-propoxy group. The second state corresponds to dissociation into an OH group and a 2-propyl radical. On the GaAs(100) surface neither adsorption of 2-propanol molecules nor emersion from liquid 2-propanol causes destruction of the As−As dimer structure.