RBS/C, XRR, and XRD Studies of Damage Buildup in Er‐Implanted ZnO

Abstract

Accumulation and transformation of defects formed in bulk ZnO crystals at room temperature upon 300 keV Er ions bombardment have been thoroughly examined using complementary techniques: Rutherford Backscattering Spectrometry in ion Channeling mode (RBS/C), X‐Ray Reflectivity (XRR), and X‐Ray Diffraction (XRD). Evaluation of RBS/C spectra has been performed using Monte Carlo (MC) simulations (McChasy software). Two defect types have been indicated: point defects (randomly displaced atoms, RDA) and extended ones (edge dislocations, DIS). Depth‐distributions of RDA and DIS turned out to be shifted toward deeper regions of ZnO crystals (relative to Er‐ions range) while DIS are localized even deeper than RDA. The MC simulations reveal three regions of defects accumulation separated by two regions of rapid defects transformation occurring at a certain critical Er fluence. Strain, suggested to be a driving force of defect transformation, has been determined using simulations of the XRD profiles based on the dynamical theory of X‐ray diffraction (MROX software). The presented research can help to better understand the interaction between impurity Er ions and ZnO target atoms during the implantation process. Hence, implantation conditions, for example, for luminescence purpose may now be more efficiently chosen based on the results discussed.