X-ray photoelectron spectroscopy and X-ray electron-microprobe analysis of single crystals based on bismuth telluride

Abstract

Experimental data on the distribution and atomic fractions of elements in Bi2Te2.94Se0.06, Bi2Te2.88Se0.12, Bi1.99Sn0.01Te2.94Se0.06, and Bi1.99Sn0.01Te2.88Se0.12 are discussed; these data were obtained using X-ray electron-microprobe analysis and X-ray photoelectron spectroscopy. It is ascertained that Sn impurity introduced with a concentration amounting to x=0.01 increases the uniformity of the Bi and Te distributions in solid solutions, whereas an increase in the Se content from y=0.06 to 0.12 gives rise to fluctuations in the composition; the fluctuations range from 0.5 at. % in undoped solid solutions based on Bi2Te3 to 0.3 at. % in these solutions doped with Sn. The binding energies of the core electrons in the single crystals under consideration were determined; variation in the total density of electronic states in the valence band in the vicinity of the Fermi level was observed.