Classical and quantum Hall effect measurements in GalnNAs/GAAs quantum wells

摘要

We have performed magneto-transport experiments in modulation-doped Ga _(0.7)In_(0.3)N_yAs_(1-y)/GAAs quantum wells with nitrogen mole fractions 0.4%, 1.0% and 1.5%. Classical magnetotransport (resistivity and low-field Hall effect) measurements have been performed in the temperatures between 1.8 and 275 K, while quantum Hall effect measurements in the temperatures between 1.8 and 47 K and magnetic fields up to 11 T. The variations of Hall mobility and Hall carrier density with nitrogen mole fractions and temperature have been obtained from the classical magnetotransport measurements. The results are used to investigate the scattering mechanisms of electrons in the modulation-doped Ga_(0.7)In_(0.3)N _yAs_(1-y)/GAAs quantum wells. It is shown that the alloy disorder scattering is the major scattering mechanism at investigated temperatures. The quantum oscillations in Hall resistance have been used to determine the carrier density, effective mass, transport mobility, quantum mobility and Fermi energy of two-dimensional (2D) electrons in the modulation-doped Ga_(0.7)In_(0.3)N_yAs _(1-y)/GAAs quantum wells. The carrier density, in-plane effective mass and Fermi energy of the 2D electrons increases when the nitrogen mole fraction is increased from y=0.004 to 0.015. The results found for these parameters are in good agreement with those determined from the Shubnikov-de Haas effect in magnetoresistance.