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Last Updated: 2/4/2011

Stephen Lehner

Affiliation/Institution: Arizona State University
Phone: 480-965-7250
Email: slehner@asu.edu
Address:
  School of Earth & Space Exploration and Department of Chemistry 
  Arizona State University 
  Tempe AZ  85287-1404 USA

Academic
University prior to coming to ASU: Vanderbilt University
Status at ASU: Postdoc
Time period at ASU: 2007 - present

My family and myself

I am married with three children, Erin, Ava, and Dylan.

EDUCATION
. PhD. Environmental Science, August 2007, Vanderbilt University. Dissertation title: Characterization of defect energy levels due to As, Co, and Ni impurities in pyrite: A step toward understanding charge transfer kinetics at the semiconductor/electrolyte interface
. M.S. Geology, August 2004, Vanderbilt University. Thesis title: The effect of impurities on the electrical properties of pyrite crystals: Studies of synthetic pyrite (FeS2) doped with As, Co, and Ni
. B.S. Geology, May 2002, Middle Tennessee State University, Cum Laude
. South Dakota School of Mines and Technology Geology Field Camp, May and June 2001
. Bachelor of Music, May 1990, Belmont University, Cum Laude

CURRENT RESEARCH - ARIZONA STATE UNIVERSITY
I am currently studying primitive meteorites with a focus on the enstatite chondrites. Enstatite chondrites may be the closest analog to the raw material that accreted to form the Earth and other terrestrial planets. I collect and analyze data primarily through the use of electron source analytical tools including the electron microprobe, the scanning electron microscope and the transmission electron microscope. The collected data are revealing the chemical and mineralogical makeup of these meteorites from micron to atomic scales. My results place important constraints on the nebular environment where these meteorites and possibly the Earth formed.

I am also building on my dissertation research by studying the electrical behavior of impurities in the semiconductor, pyrite. We are using Fourier-transform infrared spectroscopy, Hall-effect measurements, and secondary ion mass spectrometry to measure defect levels within the pyrite band gap. We are using this knowledge to synthesize pyrite thin films for photovoltaic devices in an effort to develop an inexpensive, non-toxic material for solar electrical generation.

INSTRUMENTAL TECHNIQUES
. TEM, STEM, EELS, SEM, EMPA, LA-ICPMS, Laser Raman, XRD and standard petrographic techniques to investigate the origins of enstatite chondrite meteorites
. Hall-effect measurements, FTIR, PIXE, SIMS, magneto-resistance, and photoluminescence techniques to study the electronic structure of impurity defects in synthetic pyrite


7 * M Research Group at Arizona State University
http://7starm.asu.edu/