X‐ray characterization of CdO thin films grown on a ‐, c ‐, r ‐ and m ‐plane sapphire by metalorganic vapour phase‐epitaxy

Abstract

. Ct, 81.05.Dz, 81.15.Gh CdO thin films have been grown on a-plane (11 2 0), c-plane (0001), r-plane (01 1 2) and m-plane (10 1 0) sapphire substrates by metalorganic vapour-phase epitaxy (MOVPE). The effects of different substrate orientations on the structural properties of the films have been analyzed by means of X-ray diffraction, including θ-2θ scans, pole figures and rocking curves. (111), (001) and (110) orientations are found on a-, r-, and m-sapphire respectively, while films deposited on c-plane exhibit an orientation in which no low-index crystal plane is parallel to the sample surface. The recorded pole figures have allowed determining the epitaxial relationships between films and substrates, as well as the presence or absence of extended defects. The rocking curves indicate that high quality thin films, in terms of tilt and twist, can be obtained on r-, c-and m-plane sapphire, while further improvement is needed over the a-orientation.

High-pressure Raman scattering of CdO thin films grown by metal-organic vapor phase epitaxy

“…Details on the growth conditions and structural properties of these epilayers can be found elsewhere. 8,9 Hall-effect measurements revealed that the as-grown CdO thin films display high n-type conductivity, with free-electron densities as high as 1.8 Â 10 20 cm À3 and electron mobilities around 50 cm 2 V À1 s À1 .…”

Karl Bädeker (1877-1914) and the discovery of transparent conductive materials

“…CdO thin films have been prepared on various substrates, such as glass , MgO (), GaAs (), or sapphire () with various methods, e.g., rf sputtering (), molecular beam epitaxy () or metal‐organic vapor phase epitaxy (MOVPE) . The MOVPE on sapphire has resulted in (001)’oriented thin films on r‐plane sapphire, (110)’orientation on m‐plane and (111)’orientation on a‐plane substrates ().…”

Faceting and structural anisotropy of nanopatterned CdO(110) layers

“…We have found the epitaxial relationships to be ͓110͔ CdO ʈ ͓0001͔ Sapphire and ͓001͔ CdO ʈ ͓1210͔ Sapphire , confirming our previous results. 21 The directions specified by three indices refer to CdO, while a four-index notation is used to specify sapphire directions. The fact that the epitaxial relationships have been found to be independent of growth temperature and VI/II molar ratio strongly suggests that, under our experimental conditions, the substrate surface crystallographic structure controls and determines the initial nucleation.…”