EELS AND PHOTOEMISSION-STUDY OF ANTIMONY-DOPED CD2SNO4 CERAMICS

Ceramic samples of antimony-doped dicadmium stannate Cd2Sn1-xSbxO4 pre pared in air by standard solid-state synthetic procedures have been st udied over the range 0 less than or equal to x less than or equal to 0 .05 by electron energy loss spectroscopy (EELS) and ultraviolet and X- ray photoemission spectroscopy (UPS and XPS). The maximum plasmon ener gy for doped samples is about 0.6 eV, corresponding to a carrier conce ntration of 2.4 x 10(20) cm(-3). The carrier concentration probed by E ELS always exceeds the nominal doping level by about 4.0 x 10(19) cm(- 3). UPS shows a well defined conduction band feature, whose intensity increases with antimony concentration. The shape of the conduction ban d conforms tolerably well to a parabolic free-electron-like profile. T he width of the conduction band of highly doped samples is in good agr eement with that expected from a free electron model. A pronounced seg regation of Sb to surface is evident from XPS and is discussed in deta il.