Determination of effective mass in InN by high-field oscillatory magnetoabsorption spectroscopy

We report on oscillatory magnetoabsorption experiments on several indium nitride (InN) epilayers under a pulsed magnetic field up to 56 T. This optical technique is uniquely suited to probe the bulk electronic structure in the vicinity of the fundamental band edge by Landau level spectroscopy. We discuss these results in light of two recent studies on the InN band structure by high-field magnetotransport [Goiran et al., Appl. Phys. Lett. 96, 052117 (2010)] and magneto-photoluminescence [Pettinari et al., Phys. Rev. B 79, 165207 (2009)]. In particular, we evidence a strong nonparabolicity of the conduction band and demonstrate that the electron effective mass m_e⊥0*=0.055m₀ measured by Shubnikov--de Haas oscillations is confirmed by the magneto-optical experiments.