CONFINED ELECTRON-STATES IN CORRUGATED GAAS ALAS SUPERLATTICES/

The electronic and optical properties of GaAs/AlAs superlattices grown in the [311] direction are investigated in the framework of an empiri cal tight-binding model which includes second-neighbor interactions. T he [311] superlattices are of great interest because of their non-flat interfaces and because the periodic corrugation which appears gives r ise to a lateral confinement. This results in the formation of quantum wires which present a pronounced degree of optical anisotropy. The ch aracteristics and the energy gap value of these wires are studied as f unctions of the layer thickness and the differences with [001]-grown s uperlattices are discussed. The calculated cross-over of GAMMA- and X- like levels is in good agreement with the experimental observations. T he nature of the lowest conduction states is explained in terms of the symmetry of the superlattice.