Megagauss cyclotron resonance in cubic GaN-layers

摘要

We report on the IR-megagauss cyclotron resonance of p-type cubic GaN. The Mg-doped sample layers were grown by plasma assited MBE on (001)-GaAs substrates controlled by in situ RHEED. The doping profile of the layers was determined by SIMS measurements. The carrier system was characterized by temperature dependent conductivity and Hall-effect measurements resulting for the carrier concentration in the order of 10~(17) cm~(-3) and the mobility 200 cm~2/Vs at room temperature. Using CO_2 laser radition of different wavelength the samples were investigated by megagauss cyclotron resonance in magnetic fields up to 300 T. The magnetic field was generated by the semidestructive single-turn coil technique and allows to detect transmission changes of the sample in the magnetic field in the order of 1percent of zero field transmission. The observed resonance spectra are strongly temperature dependent. The data are compared directly with the Landau level scheme of cubic GaN in the Luttinger model. Since no energy band parameters of cubic GaN are directly available from experiments, the correspondence of the band parameters for wurtzite and zincblence GaN as given by Kim et al. has been applied resulting in astonishingly realistic resonance positions and intensities. Experimental data and subsequent theoretical simulation demonstrate the high efficiency of megagauss spectroscopy by a ZOOM effect with respect to the energy levels involved and thus providing detailed information on the investigated material.