Reactions ofI2andCl2with In- and As-terminated InAs(001)

The reactions of ${\mathrm{I}}_2$ and ${\mathrm{Cl}}_2$ with InAs(001) were investigated with synchrotron-based soft-x-ray photoelectron spectroscopy and low-energy electron diffraction. ${\mathrm{I}}_2$ saturates the In-terminated InAs(001) surface, forming a well-ordered overlayer of InI, while As-terminated InAs(001) becomes disordered and forms both In and As iodides. Both the In- and As-terminated surfaces are disordered by ${\mathrm{Cl}}_2$ adsorption, forming InCl, ${\mathrm{InCl}}_2,$ and As chlorides. The differences in the behavior of ${\mathrm{I}}_2$ and ${\mathrm{Cl}}_2$ are attributed primarily to the inability of ${\mathrm{InI}}_2$ to form on the outermost surface.