Electron effective mass and $g$ factor in wide HgTe quantum wells

The magnetic-field (0 T $<B<$ 9 T) dependence of the longitudinal and Hall resistances at fixed temperatures (2 K $<T<$ 50 K) for the HgCdTe/HgTe/HgCdTe system with a HgTe quantum well 20.3 nm in width are measured. The activation analysis of the magnetoresistance curves is used as a tool for identifying the mobility gaps between neighboring Landau levels. The activation-energy values obtained from the temperature dependences of the longitudinal resistance in the plateau regions of the quantum Hall effect with the filling factors $v$ = 1, 2, 3 make it possible to estimate the effective mass and the g factor of electrons in the system under study. Indications concerning the possibility of large values of the g factor ($\cong$ 80) are obtained.