We study physical properties of organic thin films, structures,
and devices. Our fundamental findings are applied to the development
of practical optoelectronic, electronic, and photonic organic
devices of nano-scale thickness, including visible LEDs, lasers,
solar cells, photodetectors, transistors, chemical sensors, and
memory cells. In addition to working on small-molecular-weight
van der Waals bonded organic thin films, we are also examining
hybrid organic/inorganic structures, polymer solids, and self-assembled
materials. Integral to this research
is development of new methods for materials growth and techniques
for directed nano-scale patterning over large areas.
Our research facilities are located in the Research Lab of Electronics
(RLE) and the Center for Materials Science and Engineering (CMSE).
The optical characterization lab houses our spectroscopy setup
capable of detecting spectral response at very low light intensities.
Our materials growth and characterization lab presently enables
growth of molecular and polymeric organic thin films and structures
under controlled inert atmosphere.
In our integrated materials growth system we are combining the conventional materials growth techniques
with novel deposition methods developed in our laboratories.
The system integrates the method for physical
and vapor phase deposition of hybrid organic/inorganic thin-films
with a low-pressure RF/DC sputtering chamber, an evaporative
growth chamber, and a chemical vapor deposition chamber. The system is capable of depositing molecular
organics, polymers, metals, metal oxides, inorganic nanodots,
and colloids in a controlled layer-by-layer fashion. An in-situ
shadow masking system enables fabrication of complex patterned
structures inside a vacuum environment, while the integrated
N2-filled, dry glove boxes facilitates handling, measuring,
and packaging of thin film samples to protect them from reactions with atmospheric oxygen and water vapor.
The present interest in the use of organic and nanostructures thin films in optoelectronics
stems from many technological benefits intrinsic to these materials.
Nanostrcutured thin film are simple to grow over both small and large
areas, and easy to integrate with both conventional technologies
and less conventional materials such as flexible, self assembled,
or conformable substrates. Although functional use of molecules, polymers, and quantum dots
has been demonstrated in the form of light emitters, photodetectors,
optical elements, and active electronic logic components, many
basic electronic and optical properties of these solids are still
not well understood. Much research is needed. Similarities with
conventional inorganic semiconductors provide a physical framework
for further investigations, but, a large number of phenomena
in organic materials have no analog and require development of
novel physical concepts .