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 4d, Pb 5d and Te 4d absorption edges and total photoelectron yield spectra of p- and n-type SnTe polycrystals, around the Te 4d absorption edge. In both phases, the Sn 4d and Pb 5d absorptions show doublet peaks due to the excitonic transitions, while the Te 4d 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 4d absorption in c-SnTe thin films and p-SnTe polycrystals, is attributed to the transition from the Te 4d level to the hole state located near the top of the valence band.