Template-controlled mineralization: Determining film granularity and structure by surface functionality patterns

Abstract

SummaryWe present a promising first example towards controlling the properties of a self-assembling mineral film by means of the functionality and polarity of a substrate template. In the presented case, a zinc oxide film is deposited by chemical bath deposition on a nearly topography-free template structure composed of a pattern of two self-assembled monolayers with different chemical functionality. We demonstrate the template-modulated morphological properties of the growing film, as the surface functionality dictates the granularity of the growing film. This, in turn, is a key property influencing other film properties such as conductivity, piezoelectric activity and the mechanical properties. A very pronounced contrast is observed between areas with an underlying fluorinated, low energy template surface, showing a much more (almost two orders of magnitude) coarse-grained film with a typical agglomerate size of around 75 nm. In contrast, amino-functionalized surface areas induce the growth of a very smooth, fine-grained surface with a roughness of around 1 nm. The observed influence of the template on the resulting clear contrast in morphology of the growing film could be explained by a contrast in surface adhesion energies and surface diffusion rates of the nanoparticles, which nucleate in solution and subsequently deposit on the functionalized substrate.

Influence of Atomic Hydrogen, Band Bending, and Defects in the Top Few Nanometers of Hydrothermally Prepared Zinc Oxide Nanorods

“…Zinc oxide (ZnO) is a wide band gap semiconductor material with a band gap of about 3.4 eV and a large exciton binding energy at room temperature (60 meV) [1, 2]. It has unique optical and electrical properties and can be grown in various morphologies using low-cost synthesis techniques [3].…”

Template-controlled piezoactivity of ZnO thin films grown via a bioinspired approach

“…In this way the growth and morphology of the films can be easily controlled [ 27 – 29 ]. Moreover, it is possible to achieve site-selective growth of ZnO by using two templates with different functionalities [ 25 , 29 – 35 ] or to change the roughness of the growing films [ 36 ].…”

Chemical bath deposition of textured and compact zinc oxide thin films on vinyl-terminated polystyrene brushes

“…Biopolymeric templates and their structure-inducing properties are in the focus of many recent works and issued in a recent collection [ 9 – 13 ]. With respect to ZnO, bio-templates are used for tailoring the morphology and crystallite sizes of ZnO [ 13 – 23 ], whereas n-type impurity dopants (e.g., Al 3+ , Ga 3+ or In 3+ ) have a significant influence on its optical properties [ 1 – 2 24 – 33 ]. In both cases, properties can be adjusted to match the requirements for different applications.…”