Cr 3d Surface and Bulk States in Sn$\text{}_{1-x}$Cr$\text{}_{x}$Te/Cr Crystals

We report a new approach to investigate metal-semiconductor interface formation. Photoemission spectroscopy was applied in order to investigate the clean surface of a Sn$\text{}_{0.97}$Cr$\text{}_{0.03}$ Te crystal and to observe its changes under sequential deposition of small amounts of Cr atoms. In order to analyse the Cr 3d contribution to the valence band, the Fano-type resonance tuned to the Cr 3p-3d transition was used. The experiment was designed to follow the Sn$\text{}_{0.97}$Cr$\text{}_{0.03}$ Te/Cr interface formation process. At the clean Sn$\text{}_{0.97}$Cr$\text{}_{0.03}$Te surface, the Cr 3d states contribution to the valence band was found to be positioned 0.8 eV below the Fermi level. After the Cr deposition processes the contribution shifted to a higher binding energy and another contribution 5.8 eV below the Fermi level was also observed.