Nearest-neighbor distances in strained thin films of random pseudobinary semiconductor alloys: A calculational methodology

Abstract

A method, based on macroscopic elastic theory, is presented, which predicts the nearest-neighbor distances in strained pseudobinary semiconductor thin films. The method applies to films grown on the (001) face of substrates with the zincblende or diamond structure. Based on crystallographic and elastic parameters, the bond lengths are determined through minimization of the elastic energy calculated in the framework of the valence force field method. Good agreement with experimental data is obtained by considering only bond stretching terms. The effectiveness of this method is shown in a number of cases taken from literature.

Low-dimensional systems investigated by x-ray absorption spectroscopy: a selection of 2D, 1D and 0D cases

“…By performing a combined fit of Ga and As K-edges spectra (see Figure 13b-c and Table 1), they observed a stretching of the As-Ga first shell bond distances and a contraction of the As-In first shell distances with respect to the binary compounds InAs and GaAs. These distances are in agreement with the experimental [168] and theoretical [389] data discussed in the previous Section for strained In x Ga 1x As alloys. Moreover, Mino et al noticed that ΔR As-Ga is higher in the SAG then in the FIELD region and an higher structural disorder (monitored by the σ 2 values) is observed in the SAG region, however the quality of the data resulted in too high error bars that did not allow them to reliably discriminate between SAG and FIELD regions (see Table 1).…”

“…In addition, successive polarization-dependent XAS measurements have shown that the second-and thirdshell interatomic distances of In x Ga 1-x As/InP epitaxial layers under tetragonal distortion split into two subset distributions [388]. Successively, d'Acapito proposed a method to calculate bond lengths in strained layers, based on a valence force field potential, that successfully matched with the experimental results [389]. This kind of approach has been very recently applied to investigate the local structure of CdSe/ZnSe systems [390].…”

Structural and electronic characterization of nanosized inorganic materials by X-ray absorption spectroscopies

“…By performing a combined fit of Ga and As K-edges spectra (see Figure 15b-c and Table 5), they observed a stretching of the As-Ga first shell bond distances and a contraction of the As-In first shell distances with respect to the binary compounds InAs and GaAs. These distances are in agreement with experimental [125] and theoretical [126] data on strained In 0.60 Ga 0.40 As alloys on InP. Moreover they noticed that ΔR As-Ga is higher in the SAG then in the FIELD region and an higher structural disorder (monitored by the σ 2 values) is observed in the SAG region, however the quality of the data resulted in too high error bars that did not allow them to reliably discriminate between SAG and FIELD regions (see Table 5).…”

Localization of the dopant in Ge:Mn diluted magnetic semiconductors by x-ray absorption at the Mn K edge

“…Though a precise determination of the structure in case of elastic stress would require the knowledge of values of the elastic constants [34], we observed that the Mn-Ge distance did not change regardless of the Mn concentration. Our intent here was to give a first order rough estimate of the local strain as supported by the EXAFS determination of the first Mn-Ge distance close to 2.50 Å (see section 4).…”