Interactions of deposited Ca with TiSe2 and TiTe2 surfaces

The interaction of evaporated Ca with TiSe2 and TiTe2 surfaces was studied using photoelectron spectroscopy. The surfaces were held at room temperature, and the measured spectra clearly show that the deposited Ca reacted with the substrates, without formation of any Ca overlayers. For depositions on TiSe2 corresponding to less than 2 nm of Ca there were indications of an intercalation reaction taking place, with charge transfer to the TiSe2 layers, but as more Ca was added a layer-breaking reaction dominated. For the case of TiTe2 only a large Ca deposition was studied, resulting in a layer-breaking reaction very similar to that found on the TiSe2 surface for similar amounts of deposited Ca.