Project Title: ELECTROCHEMICAL PROCESSING OF NANOSTRUCTURED
MATERIALS
Investigator: Thomas P. Moffat
Technical Description:
A variety of nanostructured materials may be synthesized by electrochemical deposition. Our
effort currently is focused in two areas: a) electrodeposition of low dimensional structures
such as multilayers and b) in-situ characterization of the structure and dynamics associated
with technically relevant processes that occur at solid/electrolyte interfaces. In particular, the
role of inorganic and organic adsorbates on the evolution of thin film microstructure and
morphology are of particular interest.
Technical Objectives:
- Develop and optimize methods for producing well defined metallic thin films via
electrochemical processing. Study the evolution of epitaxial structure and
morphology during film growth. Apply the knowledge gained to the growth of
multilayered materials with a well defined modulation orientation and defect structure.
- Develop the use of scanning probe microscopy (SPM) to characterize the structure and
dynamics of the electrode/electrolyte interface. Explore the feasibility of using SPM
as a nanostructural synthesis tool via implementation of spatially localized
electrochemical reactions.
- Investigate the mechanisms by which organic molecules and inorganic anions
influence the microstructural and morphological evolution of electrodeposited metal
films.
- Develop an inexpensive means for high resolution patterned electrodeposition.
Anticipated Outcome:
- Produce well defined model strained-layer superlattices for property measurements by
several other researchers. These materials exhibit technically interesting magnetic and
mechanical properties.
- The commercial success of electroplating technologies stems largely from the
remarkable influence of electrolyte additives on the physical properties of the
deposited films. Our SPM studies promise to provide considerable insight into the
way these adsorbates influence microstructural evolution.
- Provide a means for inexpensive, low capital cost, patterned electrodeposition of
metals.
Accomplishments for FY 1995:
- Heteroepitaxial deposition of nickel on copper is being explored in order to develop
the capability to produce a variety of Cu-(Ni,Co,Fe) metallic superlattices with
rigorously defined modulation orientation. To date we have produced a series of
multilayers on Cu(100) with modulation wavelengths ranging from 2.6 nm to 70 nm
oriented exclusively in the <100>. These films typically cover an area of ~2.5 cm2
and are ~2.4 µm to 4.7 µm thick. The mechanical and magnetic properties of these
materials are being examined by several other researchers at NIST. In contrast to the
specular films grown on Cu(100), growth on Cu(111) and Cu(110); leads to roughened
surfaces. The origin of this instability along with the potential use of surfactants to
control interfacial morphology is being explored.
- Developed the capability for studying the structure and dynamics of the
deposition/dissolution of Cu and Ni with atomic resolution in-situ scanning tunneling
microscopy.
- In a collaboration with H. Yang of IGEN Inc. we have demonstrated the use of self-
assembling monolayers (SAM) as masks for pattern plating. Micrometer level features
were easily and inexpensively synthesized by contact printing of the SAM's followed
by electrodeposition in a typical chemical laboratory environment. Looking to the
future we would be able to use this mask technology for pattern electrodeposition in
the nanometer regime using SPM, electron beam technology or possibility contact
printing.
Impacts and Technical Highlights: