Experimental observation of two-dimensional electron gas in the CdS quantum wells of CdS/ZnSe heterostructures

We report the observation of a two-dimensional electron gas (2DEG) in the C dS quantum wells of CdS/ZnSe quantum heterostructures grown by molecular be am epitaxy. The CdS layers are about 4 nm thick; the thicknesses of the ZnS e-doped layers and the growth temperatures of the heterostructures were var ied in order to investigate their influence on the 2DEG parameters. The eff ective sheet concentration of the 2DEGs reached up to 1.5 x 10(13) cm(-2). The maximal Hall mobilities were nevertheless still inferior or equal to 38 0 cm(2)/V s. Possible scattering mechanisms that cause such low values are discussed. Most probably, it is scattering by stacking faults or by interfa ce roughness. (C) 1999 American Institute of Physics. [S0003-6951(98)01750- 1].