Chapter 2 Magneto-Optical and Electrical Detection of Paramagnetic Resonance in Semiconductors

Abstract

This chapter discusses the magneto-optical and electrical detection of paramagnetic resonance in semiconductors. Electron paramagnetic resonance (EPR) is a powerful tool for the study of the microscopic and electronic structures of point defects in nonmetallic solids. In the conventional detection of EPR, upon the induction of a magnetic dipole transition between the Zeeman levels of the defect, a microwave absorption is measured in a microwave bridge. A higher resolution of hyperfine (hf) and superhyperfine (shf) interactions is achieved by electronuclear double-resonance (ENDOR), where nuclear magnetic resonance (NMR) transitions are detected via an EPR transition (i.e., ENDOR is a double-resonance method). Usually in semiconductors, the ENDOR effect is, at most, about a few percentages of the EPR effect, which requires, accordingly, a higher number of defects. The optical detection of EPR (optically detected electron paramagnetic resonance [ODEPR]) differs from conventional detection basically in that a microwave-induced repopulation of Zeeman levels is detected indirectly by a change of some properties of light, which is either absorbed or emitted by the defect under study.