NaandCl2Interaction on it and 2H–TaSe2(0001) Surfaces

In this paper we study the interaction ofCl2and Na on 1T–TaSe2and 2H–TaSe2(0001)surfaces in the temperature range of 100–300 K. The experiments are performed in UHV with the use of LEED and SXPS by synchrotron radiation measurements. Deposition of Na onCl2-covered 1T–TaSe2at 100 K forms initially a${\rm Na}\mbox{-}{\rm Cl}_2^-$, which with increasing temperature to 300 K leads to NaCl formation. Adsorption ofCl2on Na-intercalated 1T and 2H–TaSe2surfaces at 100 K formsCl2multilayers. The firstCl2layer, in contact with the substrate, interacts with the Na near the surface and forms${\rm Na}\mbox{-}{\rm Cl}_2^-$. Warming up to 300 K leads to partial desorption ofCl2, while the remaining chlorine interacts strongly with Na, causing the deintercalation of Na to the surface in the tendency to form NaCl. The intercalation–deintercalation process takes place across the van der Waals planes and it is much faster on 2H than on 1T–TaSe2, which is attributed to the different crystal structure of 2H and 1T ofTaSe2.