Electron channelling analysis of aluminium and xenon-implanted aluminium

Abstract

Characteristic X-ray emission from unimplanted aluminium is measured under near zone axis diffraction conditions. X-ray emission rates change by factors of 2–3 as the crystal is tilted with respect to a 120 keV incident electron beam. The probability density ϕϕ ∗ of the fast electron wavefunction on atomic sites is calculated and correlated with the observed Kikuchi band structure and characteristic X-ray count rate. A plot of X-ray count rate versus ϕϕ ∗ yields an approximately linear relationship, permitting a measurement of an “incoherent background” contribution to the count rate. ALCHEMI analysis is used to probe the interface between small 2–3 nm diameter solid xenon particles and an aluminium matrix, where the fcc xenon lattice parameter is 1.5 times that of aluminium. Although a relatively strong channelling effect is observed for characteristic X-ray emission from the implanted aluminium matrix, emission from the solid xenon precipitates is insensitive to electron diffraction conditions. This suggests that the aluminium/xenon interface is incoherent, a conclusion supported by previous lattice imaging experiments and their comparison with calculated images.