Stopping and straggling of H and He in ZnO

Abstract

We present experimental and theoretical values for the energy loss of H and He ions in Zinc oxide, in mean value (stopping per unit path length) and mean square value (energy loss straggling). The measurements were carried out using the Rutherford Backscattering technique for (300–2000) keV H ions and (300–5000) keV He ions. Present experimental data are the first set of stopping and straggling values in this oxide. The theoretical research was encouraged considering the molecular description of ZnO as crystal solid using the density functional theory. The energy loss calculations for H and He ions with different charge states were performed with the shelwise local plasma approximation (SLPA). The molecular versus the Bragg-rule description is also discussed. The equilibrium charge state of He inside ZnO is analyzed based on the present stopping measurements, and a semiempirical charge state distribution is proposed. Present experimental and theoretical values show good agreement for both the stopping and the straggling. We also compare our data with the SRIM2013 and with CasP5.2 values.