Investigation of magnetic quantum and resonance effects in two-dimensional semiconductor systems by contactless methods

The investigation of the Shubnikov-de Haas (SdH), cyclotron resonance and Hall effects in two-dimensional (2D) semiconductor systems GaAs/Al/sub x/Ga/sub x-1/As are presented. The function of magnetic-field-dependent of the derivatives of the reflection coefficient of the microwave power and the period oscillation SdH are obtained. With these data the carriers concentration n, mobility /spl mu/ electrons and Hall-resistance /spl rho//sub 12/ are determined.