REFLECTION HIGH-ENERGY ELECTRON-DIFFRACTION STUDY OF THE GROWTH OF NIO AND COO THIN-FILMS BY MOLECULAR-BEAM EPITAXY

NiO thin films have been prepared under UHV conditions by metal evaporation on both ex-situ and in-situ cleaved MgO(100) using O-2 and NO2 as oxidants. Changes in the film morphology are monitored with reflection high-energy electron diffraction (RHEED). While it is possible to grow films epitaxially using O-2, we find films grown using NO2 to be of superior quality, Using NO2 as an oxidant, films synthesized between 200 and 450 degrees C grow layer by layer, while an increase in surface disorder is observed in films grown below 200 degrees C. Pronounced RHEED intensity oscillations are observed for 200