Photoemission studies of the conduction band filling in and Cs-intercalated and

We have used photoelectron spectroscopy to study the filling of conduction band states of the layered semiconductors and as they are intercalated by Cs. Comparison is also made with `self-intercalated' . Even in the pure samples, occupied conduction band states due to excess Ti/Zr are found, but this occupancy is greatly increased by Cs intercalation. The stoichiometries are estimated from the extent in k -space of the occupied bands. A weak structure just below the conduction band minimum of is tentatively attributed to localized defect states.