IMR: Acquisition Of An Electron Paramagnetic Resonance Spectrometer For Defect Analysis Research And Materials Physics Education

University Of Alabama At Birmingham, Birmingham AL

Investigators

Abstract

EPR is known for its ability to determine the detailed electronic structure of point defects in a wide variety of materials. Decades of investigations have produced a huge database of defects so that today the technique may also be used as a general characterization tool. The dual nature of the technique enables its use for major research investigations as well as for basic education and training. Students studying diamond thin films and chemistry students probing electron transfer reactions in transition metal complexes have used the instrument to further their studies. Sensitivity is a particularly significant issue for us because defect densities in electronic materials are generally below 1 part in 105, and the signal-to-noise ratio of the present system is only 40% of its optimal value. This results in extensive signal averaging and limits our ability to detect certain centers. The new system will minimize data acquisition time and allow for lower numbers of defects to be observed. Our studies utilizing EPR directly affect the semiconductor industry by contributing a basic understanding of the low concentration of intrinsic defects and impurities required to produce the high quality material necessary for the high power, high frequency applications. Electronic paramagnetic resonance is used to study electronic defects in a wide variety of materials. The technique is used for major research investigations as well as for basic education and training. We are working to improve the detection limits of our instruments in order to study defects that occur at lower concentration levels. Our studies utilizing EPR directly affect the semiconductor industry by contributing a basic understanding of the low concentration of intrinsic defects and impurities required to produce the high quality material necessary for the high power, high frequency applications.