GRADED POTENTIAL WELLS WITH QUASI-UNIFORM CHARGE-DISTRIBUTION

We report on the growth and the characterization of several quasi-three-dimensional electron systems as realized in modulation-doped graded potential wells. We study the charge distribution, the subband structure, and the electronic properties of the samples by means of capacitance-voltage techniques as well as by the investigation of the cyclotron resonance at low temperatures. The results of our investigations are fed back into the growth conditions, which leads to the production of symmetrical, quasi-uniform charge distributions with three-dimensional properties. © 1990.