X-ray photoelectron spectroscopy on amorphous CuxTe100−x and NixTe100−x

Abstract

The electronic structure of amorphous and crystalline Cu_xTe_100−x and Ni_xTe_100−x alloys was investigated by analysing the core levels measured using X-ray photoelectron spectroscopy. The binding energies of the core levels and their full width at half-maximum yield information on the atomic and electronic structure of the samples, and the asymmetry of the core levels correlates with the density of states of the elements at the Fermi level. Tellurium electron states seem to dominate the electronic properties of the CuTe samples. Three metal-to-semiconductor transitions were observed in Cu_xTe_100−x around x = 45, and above and below x = 65. The last two transitions correspond to the electrical conductivity observed in melts. No transition was observed in Ni_xTe_100−x in the range 37 < x < 63 but we expect one for x below 37.