Modification of the structure of ZnO : Al films by control of the plasma parameters

ZnO:Al films were deposited by RF magnetron sputtering in triode configurat ion applying an external DC electric field to the substrates. Reflection hi gh-energy electron diffraction measurements characterized the different fil ms as consisting of randomly-oriented zinc blende crystallites or randomly and texture-oriented wurtzite crystallites, as well as of the amorphous pha se. The non-resonant Raman spectra are strongly influenced by the presence of a built-in electric field at the grain boundaries and they do not depend on the symmetry of the microcrystallites. The Raman spectra taken at reson ant excitation are more sensitive to the presence of the amorphous phase in the films. (C) 2001 Elsevier Science B.V. All rights reserved.