PNNL-13501 - Pacific Northwest National Laboratory

Synthesis and Characterization of Interfaced Cu2O Nanostructures
Study Control Number: PN00083/1490
Yong Liang, Scott A. Chambers, H. Luo
Quantum dots are often cited as an exciting new class of nanomaterials for use in optical and photosynthetic applications.
In this project, Cu2O quantum dots are grown on SrTiO3 and their properties are characterized.
Project Description
Three-dimensional structures on a length scale of a few to
a few tens of nanometers exhibit properties of a particlein-zero
dimension. Such nanostructures are often referred
to as quantum dots or quantum particles. This project is
aimed at investigating the properties of self-assembled
Cu2O. Cooper oxide (anatase) is an important material
system in energy and environmental research. We use
molecular beam epitaxial methods to synthesize Cu2O
quantum dots on SrTiO3 substrates, and characterize the
morphological, electronic, and optical properties of these
quantum dots using a number of surface, laser
spectroscopic, and microscopic techniques.
Results and Accomplishments
We completed all the proposed tasks. These were 1)
synthesis of self-assembled Cu2O quantum dots on SrTiO3
substrates, 2) determining morphological and electronic
properties of Cu2O/SrTiO3 using atomic force microscopy
and x-ray photoelectron spectroscopy techniques, and
3) investigation of photoluminescence properties of Cu2O
quantum dots. We also successfully synthesized Cu2O
nano-corrals on SrTiO3 substrates. These results
demonstrated our ability to synthesize and characterize
these oxide nanostructures, a class of materials of
potential significance in energy and environmental
research.
Synthesis of Cu2O Quantum Dots
We successfully synthesized Cu2O quantum dots on
SrTiO3 substrates using molecular beam epitaxial method.
Figure 1 is an atomic force microscopy image that shows
Cu2O quantum dots self-assembled on a SrTiO3 substrate.
Results show that most of the Cu2O quantum dots have
the same lateral orientations at the surface, suggesting a
high degree of crystal graphic coherency among these
dots, and an excellent structural registration between the
dots and the SrTiO3 substrate. By controlling the copper
flux, substrate temperature, and growth time, we have
354 FY 2000 Laboratory Directed Research and Development Annual Report
Figure 1. An atomic force microscopy image showing selfassembled
Cu 2O quantum dots grown on an SrTiO 3
substrate. The size of the image is 1x1 µ.
been able to control the average size of these quantum
dots with lateral size from less than 10 nm to nearly
100 nm. We have also characterized the quantum dots
with x-ray diffraction. Results confirmed that the
quantum dots grown on SrTiO3 under appropriate
conditions had a Cu2O crystal structure, as demonstrated
in Figure 2.
SrTiO3O
Cu2O
Figure 2. X-ray diffraction showing that quantum dots
grown on a SrTiO 3 substrate have a Cu 2O crystal structure