Mentor: Darrell Schlom

Mentor's Responsibility for PARADIM:  Platform Director

REU intern:  Joseph Dill

Darrell Schlom is the Herbert Fisk Johnson Professor of Industrial Chemistry in the Department of Materials Science and Engineering at Cornell University. After receiving a B.S. degree from Caltech, he did graduate work at Stanford University receiving an M.S. in Electrical Engineering and a Ph.D. in Materials Science and Engineering. He was then a post-doc at IBM's research lab in Zurich, Switzerland in the oxide superconductors and novel materials group managed by Nobel Prize winners J. Georg Bednorz and K. Alex Müller. In 1992 he joined the faculty at Penn State in the Department of Materials Science and Engineering, where he spent 16 years before joining the faculty at Cornell in 2008. His research interests involve the heteroepitaxial growth and characterization of oxide thin films by reactive molecular-beam epitaxy (MBE), especially utilizing a 'materials-by-design' approach to the discovery of materials with properties superior to any known. His group synthesizes these oxide heterostructures using molecular-beam epitaxy (MBE). He has published over 550 papers and 8 patents resulting in an h-index of 75 and over 28,000 citations. He has received various awards including an Alexander von Humboldt Research Fellowship and the MRS Medal, is a Fellow of both the American Physical Society and the Materials Research Society, and is a member of the National Academy of Engineering.

Project Title: 

Design of an Improved Ozone Injector Nozzle for Oxide Molecular-Beam Epitaxy

Research question that defines the REU student's project:

What changes should be made to the current ozone nozzle to provide a more even distribution of ozone at the growth surface?

Project Description: 

When oxides are grown by molecular-beam epitaxy (MBE), the oxygen molecules are supplied by ozone (O₃) as it is significantly more reactive than oxygen gas (O₂). PARADIM's MBE machine currently delivers ozone to the growth surface via a single nozzle pointed at the center of the sample. This design provides the most ozone at the center, but significantly less ozone at the edges. For small samples this works fine, but when large oxide samples are grown in this chamber the lack of ozone in the outer region results in the grown crystal structure to be oxygen deficient at the edges. In this project, the REU student will design a new ozone nozzle that provides a more even (but still high) distribution of ozone across the entire growth surface.

Project plan/research task to answer the research question:

Write a computer simulation that models the emission of gas molecules in the molecular flow regime from multiple nozzles onto a surface. Computationally determine the parameters (length, diameter, orientation, etc.) of one or more pipes that optimize the flux of ozone onto the sample. Use CAD software to design a nozzle that matches the optimized parameters identified in the simulation.

List of tasks to be performed by the REU student and tasks to be performed by the mentor to answer the research questions:

Task for REU student: Computer simulation (Mathematica), nozzle design (Solidworks).Task for Mentor: Provide feedback to the REU student regarding the accuracy of the simulation and feasibility of the nozzle design.