Alpha-emission channeling investigations of the lattice location of Li in Ge

Abstract

The α-emission channeling and blocking technique is a direct method for lattice site determination of radioactive atoms in single crystals. Position-sensitive detection of emitted α-particles provides an efficient means of carrying out such experiments at very low doses (10 10–10 11 cm −2 implanted probe atoms per spectrum). Comparison of the experimental data with Monte Carlo simulations of complete two-dimensional channeling patterns (e.g. ± 2° around 〈100〉, 〈110〉 and 〈211〉 axes, which also includes all relevant planar directions) allows for straightforward identification and quantitative determination of occupied lattice sites, while at the same time the energy spectrum of emitted α-particles gives information on the probe atom depth distribution. We illustrate this for the case of ion implanted 8Li ( t 1 2 = 0.8 s ) in Ge, where we identify mainly tetrahedral Li at room temperature, and bond-centered Li at slightly elevated temperature.