Spectroscopy of muon centres in n-type silicon carbide

We propose to continue laser spectroscopy measurements of the muonium (Mu-) centres in n-type doped silicon carbide. Scanning a wide wavelength range, and changing the relative timing of the muon and laser pulses, should allow us to distinguish direct muonium centre ionisation from other absorption bands within the band gap which result in free minority carriers (holes). Any peaks or absorption edges can be followed as a function of temperature, giving a direct measure of the energy levels involved.