Core Absorption Spectra of SnTe and PbTe in Crystalline and Amorphous Phases

Absorption spectra of polycrystalline and amorphous thin films of SnTe and PbTe have been measured around the Sn 4 d , Pb 5 d and Te 4 d absorption edges and total photoelectron yield spectra of p - and n -type SnTe polycrystals, around the Te 4 d absorption edge. In both phases, the Sn 4 d and Pb 5 d absorptions show doublet peaks due to the excitonic transitions, while the Te 4 d absorption shows broad structures reflecting the density of states of the conduction band. The doublet peaks in the crystalline phases are explained in an atomic picture. A small peak found below the broad structures of the Te 4 d absorption in c -SnTe thin films and p -SnTe polycrystals, is attributed to the transition from the Te 4 d level to the hole state located near the top of the valence band.