Lattice Site Location Studies of Rare-Earths Implanted in ZnO Single-Crystals

In this work we report on the lattice site location of rare earths in single-crystalline ZnO by means of the emission channeling (EC) technique. Following low dose (3 $\times 10^{13}$at/cm$^{2}$) 60 keV ion implantation of the precursor isotope $^{169}$Yb, a position-sensitive electron detector was used to monitor the angular distribution of the conversion electrons emitted from $^{169}$Tm$^{*}$ as a function of the annealing temperature up to 600$^\circ$C in vacuum. An additional annealing at 800$^\circ$C in flowing O$_{2}$ was performed. The EC measurements revealed that around 95-100% of the rare earth atoms occupy substitutional Zn sites up to an annealing temperature of 600$^\circ$C/vacuum. After the 800$^\circ$C/O$_{2}$ annealing, the emission channeling effects decreased considerably.