Research Interests
Research Description
My group's research interests are in surface chemistry, specifically the chemical processes used to clean, etch, or deposit on the surfaces of solids, including 2D planes and 3D nanostructures. An understanding of surface chemistry can be used to optimize existing materials used in microelectronics, catalysis, or solar energy conversion and develop new materials with unique properties. The primary research goals are learning how chemical reactions take place on surfaces and how the atom or molecular group terminating a surface affects the types of structures that can be built on it or using it as a building block. Understanding the reaction mechanism provides a means to rationally design interfaces for specific purposes. Current research projects include 1) engineering the surfaces of semiconductors (GaAs, InAs, InGaAs, CuInS2) for advanced electronic, optoelectronic, and solar devices, 2) synthesis and self-assembly of nanoparticles such as quantum dots (clusters of atoms 1-5 nm in diameter), 3) self-assembled monolayer (SAM) formation, and 4) dealloying metal alloys using liquids and supercritical fluids to make nanoporous noble metal films and composites. We approach these problems by using experiments and modeling to understand the mechanisms of the surface chemical reactions that are at the heart of these technologies.Experimental Capabilities
We have both wet and dry (vacuum) facilities for processing and fabricating devices using a range of materials. The wet processing includes standard chemistries for cleaning and etching semiconductor surfaces. There is a separate fume hood for synthesizing semiconductor and metal quantum dot and colloidal suspensions. There are two high pressure reactors for supercritical CO2 processing. The vacuum apparatus consists of a series of reactors connected together to avoid air exposure of samples between processing steps. There are reactors for HF/vapor, UV photochemistry, and atomic layer deposition (ALD) of oxide dielectrics, and molecular vapor deposition (MVD). In addition, we have furnaces for annealing samples in reactive and inert gases.
The characterization facilities within the group include x-ray photoelectron spectroscopy (XPS), Auger electron spectroscopy, Fourier transform infrared (FTIR) spectroscopy, ellipsometry, mass spectroscopy including temperature programmed desorption (TPD), atomic force microscopy (AFM), goniometry (contact angle), and optical characterization using photoluminescence (PL), photoluminescence excitation (PLE), and UV-visible spectroscopy. The electrical device testing apparatus is equipped with LCR meters and probe station.