Location of deuterium on the silicon (100) monohydride surface determined by transmission-ion channeling

The location of deuterium (D) in the monohydride configuration on the silicon (100) surface is established using transmission-ion channeling. A 2-MeV ${}_{}{}^4{}_{}{}^{}\mathrm{He}_{}^{+}{}_{}{}^{}$ ion beam was used to elastically recoil D from the beam-exit surface of a thin silicon crystal. The yield of recoiled D was measured versus angle about the 〈100〉, 〈110〉, and 〈111〉 axes. The location of the surface D relative to the silicon lattice was determined by comparing the measured yields with computer-channeling simulations. The observed location is consistent with a Si-D bond length of 1.6±0.2 Å along the silicon tetrahedral bond direction in agreement with recent ab initio theoretical calculations.