X-RAY-DIFFRACTION STUDY OF CORRUGATED SEMICONDUCTOR SURFACES, QUANTUM WIRES AND QUANTUM BOXES

We show that high-resolution double-crystal X-ray diffraction is not only sensitive to the periodic structural modulation normal to the crystal surface as it occurs in semiconductor superlattices, but is under appropriate experimental conditions also very sensitive to the periodic modulation parallel to the crystal surface (surface grating). This fact allow us to study the structural properties, geometrical parameters and strain state, of quantum wires and quantum boxes. We present experimental results on AlGaAs/GaAs and InAs/GaAs quantum wires and show that the quantum wire period and quantum wire width can be determined very precisely. In addition, we found a partial elastic strain relaxation normal to the quantum wires, resulting in an orthorhombic lattice deformation.