X-ray reflectivity from ZnSe/GaAs heterostructures

Abstract

Local interface composition and extended defect density in ZnSe/GaAs(001) and ZnSe/In 0.04 Ga 0.96 As (001) heterojunctions J.ZnSe/GaAs heterostructures have been studied using x-ray reflectivity. Two samples grown by molecular beam epitaxy ͑MBE͒ differed in initial growing conditions; the first was prepared by Se treatment of a GaAs substrate, and the second one was exposed to Zn before growth of the ZnSe film. The structure and morphology of the interface between the ZnSe film and GaAs substrate were investigated. The experimental x-ray reflectivity curves, measured at different wavelengths, were simulated using a distorted-wave Born approximation method. Fitting the experimental data indicated the presence of a Ga 2 Se 3 transition layer between the ZnSe film and GaAs substrate for the Se-treated sample, confirming that Zn treatment during the MBE growing process improves the interface quality. Furthermore, the simulations indicated that the concentration of the Ga 2 Se 3 was less than unity. From this, we propose that the transition layer is discontinuous, e.g., possesses an island-like morphology.

Specular and non-specular x-ray scattering study of SiO2/Si structures

“…The principal characteristics of the interface, such as roughness and surface fractal profile (jaggedness), as well the film thickness and bulk electronic density can be extracted by utilizing x-ray methods. The measurement of x-ray scattering with different geometries and detection methods yields complete information about the subnanometre structure of the sample [15][16][17][18][19][20][21].…”

“…the lateral correlation length and fractal dimension of surface imperfections. Both techniques are widely utilized [15][16][17][18]20] for the characterization of nanostructures.…”

Anion variations at semiconductor interfaces: ZnSe(100)/GaAs(100) superlattices

“…[12][13][14][15][16][17][18][19][20][21][22][23][24][25] On the free GaAs͑100͒ surface, this ␤2 structure is characterized by two As dimers in the top layer and one Ga dimer vacancy in the second layer that exposes a third As dimer in the third layer. Therefore, it is of practical interest to investigate those interfaces that might reasonably arise from real substrate surface structures.…”

The Role of Development of the Rotating Anode X-ray Generator and the Use of Imaging Plates in Powder Diffractometer Instrumentation

“…This is the first observation of in-plane diffraction from a polycrystalline thin film using a homelaboratory X-ray source and not using an SR source. The new parallel X-ray beam has interesting applications to the study of interfacial roughness and to the structural study of thin films (22)(23)(24).…”