Exciton spectra in MoSe2

Wavelength-modulated reflectivity spectra have been performed on 2H MoSe₂ at temperatures from 3.1 to 300 K. The A exciton series for which the n = 3 state was observed for the first time is shown to be anomalous with a Rydberg of 109 meV and a reduced effective mass of 0.62m_o. Several additional structures are observed and interpreted as well; in particular, the first two excited states of the B exciton, seen here for the first time, allow the determination of the parameters of that exciton series. No shift in any of the spectral structures was observed in magnetic fields of up to 7.0 T.