| Popis: |
We have measured the secondary-electron (SE) yield in coincidence with 1\char21{}2-MeV ${\mathrm{He}}^{+,2+}$ ions reflected from a SnTe(001) at grazing incidence. Specific ion trajectories, i.e., true specular reflection and subsurface channeling, can be distinguished in the energy spectrum of the reflected ions. By selecting the specific trajectories, above- and below-surface SE production processes are separately studied. The position-dependent SE production rate for 2-MeV ${\mathrm{He}}^{2+}$ is found to be about four times larger than that for 0.5-MeV ${\mathrm{H}}^{+},$ indicating that the SE production rate at the surface is proportional to ${q}^{2}.$ Analyzing the SE number distributions for subsurface channeled ions, the mean free path of SE's in SnTe is estimated to be 0.6 nm. |
