Stopping and straggling of H and He in ZnO

Abstract

We present experimental and theoretical values for theenergy loss of H and He ions in Zinc oxide, in mean value (stoppingper unit path length) and mean square value (energy lossstraggling). The measurements were carried out using the RutherfordBackscattering technique for (300-2000) keV H ions and (300-5000)keV He ions. Present experimental data are the first set of stoppingand straggling values in this oxide. The theoretical research wasencouraged considering the molecular description of ZnO as crystalsolid using the density functional theory. The energy losscalculations for H and He ions with different charge states wereperformed with the shelwise local plasma approximation (SLPA). Themolecular vs the Bragg-rule description is also discussed. Theequilibrium charge state of He inside ZnO is analyzed based on thepresent stopping measurements, and a semiempirical charge statedistribution is proposed. Present experimental and theoreticalvalues show good agreement for both the stopping and the straggling.We also compare our data with the SRIM2013 and with CasP5.2 values.