Defects, spins and charge transport

Synopsis

When defects are paramagnetic, magnetic resonance becomes a powerful tool to help to understand their elemental composition, structure and electronic level scheme. Unfortunately, the conventional detection of electron paramagnetic resonance via magnetization measurements is rather insensitive. However, it was realized at least already in the 1960s e.g. by Schmidt, Solomon and colleagues, that spin selection rules can influence charge transport in semiconductors, allowing the highly sensitive detection of paramagnetic defects and of their impact on device performance. A recent highlight is the readout of the spin state of single NV- centers in diamond via “simple” room temperature photoconductivity experiments.

The talk will introduce the most important spin-to-charge conversion methods developed over the last years, including both spin-dependent recombination as well as spin-selective excitation, and will discuss some topical examples including dopants in silicon, loss processes in solar cells and vacancies in wide-gap semiconductors.

This work is supported by Deutsche Forschungsgemeinschaft through the Priority Program on New Frontiers in Sensitivity for EPR Spectroscopy and the Munich Center for Quantum Science and Technology MCQST.