TEMPERATURE-DEPENDENT ANGLE-RESOLVED PHOTOEMISSION-STUDY OF THE LINEWIDTH OF SURFACE-STATES OF III-V SEMICONDUCTORS

The electron-phonon interaction involving semiconductor surface states is studied on the basis of the temperature dependence of their photoemission linewidths. Measurements of the anion-derived dangling-bond and bridge-bond surface states at critical points for InSb, GaSb, InAs, and GaAs (110) cleaved surfaces were made between 90 and 500 K using high-resolution angle-resolved photoemission spectroscopy. The values of the linewidth determined for T = 0 K lie between 246 +/- 20 and 416 +/- 10 meV and are much larger than those found for metal surfaces. In addition to the intrinsic lifetime, there appears to be a contribution to the surface-state linewidth from surface defects such as steps, that are always present to some degree on cleaved surfaces. The localized nature of semiconductor surface states makes them strongly sensitive to such defects. The temperature coefficients lie between 0.18 +/- 0.05 and 0.38 +/- 0.04 meV/K for the dangling-bond surface states and between 0.07 +/- 0.05 and 0.13 +/- 0.04 meV/K for the bridge-bond surface states. We also consider the possible effect of plasmon interactions by studying highly doped (p approximately 10(19) cm-3) GaAs samples.