E. M. Pashaev

Structural diagnostics of 'quantum' layers by X-ray diffraction and standing waves

We analyze the possibility for simultaneous adequate treatment of angular dependencies of the X-ray diffraction reflectivity and photoelectron yield (X-ray standing waves method) in order to extract the structural characteristics of semiconducting materials with ultra fine inclusions. Facilities of such an approach for evaluation of the degree of structural perfection of the layers, the phase shift of upper layers with respect to the buffer, the lattice parameters of particular layers and interfaces between them are demonstrated within the analysis of heterostructures based on the Si matrix with the Si1-xGex quantum wells and on the GaAs matrix with the InAs quantum dots.

Study of structural properties of InxGa1−xAs/InyAl1−yAs heterosystems on InP substrates

The structural properties of InxGa1−xAs/InyAl1−yAs samples on InP substrates are studied as functions of growth conditions by the method of high-resolution diffractometry. The results obtained and the photoluminescence spectroscopy data are used to optimize the technology of preparation of high-quality heterostructures with sharp interfaces. The parameters of the two-dimensional electron gas of such heterostructures measured at 77 and 300 K are comparable with the best world standards in this field, so these heterostructures may be used to manufacture transistors and integral amplifiers operating at the frequency 40 GHz and even higher.

X-ray diagnostics of P-HEMT AlGaAs/InGaAs/GaAs structures

The structural characteristics of the P-HEMT AlGaAs/InGaAs/GaAs heterostructure have been studied by high-resolution X-ray diffractometry. The parameters of the heterostructure layers were determined by simultaneous analysis of the X-ray reflection curves for the (004) and (113) crystallographic planes. Interface diffusion has been established for the InyGa1−yAs quantum well and the AlxGa1−xAs spacer layer, which are characterized by reconstructed profiles of the lattice parameter distribution and anisotropic distribution of random displacements in the layer plane and in the perpendicular direction.