c-texture versus a-texture low pressure metalorganic chemical vapor deposition ZnO films: Lower resistivity despite smaller grain size

Recently, it has been shown that it is possible to tune the morphology of zinc oxide films deposited by low-pressure metalorganic chemical vapor deposition (LP-MOCVD) while preserving good electrical conductivity. Here a closer look is taken at films deposited under two different deposition conditions; one leading to LP-MOCVD a-texture (i.e., with the a-axis perpendicular to the substrate), the other resulting in c-texture (i.e., with the c-axis perpendicular to the substrate), with the aim of correlating their structural and electrical characteristics. We introduce the concept of a "selection layer" to indicate the initial region of growth that precedes the establishment of a clear preferential crystallographic film orientation. With a strong preferential c-texture of initial nucleation the selection layer for c-texture films is minimal (