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

• Published in: Thin solid films 2014-08, Vol.565, p.1-6
• Main Authors: Fanni, L., Aebersold, B.A., Alexander, D.T.L., Ding, L., Morales Masis, M., Nicolay, S., Ballif, C.
• Format: Article
• Language: English
• Subjects: Carrier mobility; Chemical vapor deposition (including plasma-enhanced cvd, mocvd, etc.); Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Crystallographic orientation; Deposition; Electrical properties of specific thin films; Electrical resistivity; Electronic structure and electrical properties of surfaces, interfaces, thin films and low-dimensional structures; Exact sciences and technology; Grain boundaries; Grain boundary; Low-pressure metalorganic chemical vapor deposition; Materials science; Methods of deposition of films and coatings; film growth and epitaxy; Physics; Resistivity; Selection layer; Structure and morphology; thickness; Surface morphology; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Texture; Texture coefficients; Theory and models of film growth; Thin film structure and morphology; Transport; Transport mechanisms; Zinc oxide
• ISSN: 0040-6090; 1879-2731
• DOI: 10.1016/j.tsf.2014.06.033

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 (