Authors’ contributions SZR fabricated and measured the cross-poin

Authors’ contributions SZR fabricated and measured the cross-point memory devices under the instruction of SM. SM arranged and finalized the manuscript. Both authors contributed to the preparation and revision of the manuscript and approved it for publication.”
“Background In the last YM155 cell line decades, semiconductor quantum dots (QDs) have been extensively investigated because they are attractive

structures for electronic and optoelectronic advanced devices [1–3]. The characteristics of these QDs can be modified by controlling the growth parameters in order to fulfil the requirements of each device. Often, well-ordered and similar-sized QDs are required in order to take advantage of their discrete energy levels for intermediate band solar cells [4], lasers [5], and photodetectors [6]. This order can be achieved by stacking Volasertib mw several layers of QDs forming a QD matrix or superlattice. During the epitaxial growth, the strain fields of the buried QDs have

a large influence in the formation of the subsequent C646 cell line layer as it determines the nucleation sites of the incoming stacked QDs [7, 8]. The complex strain fields around a QD can produce vertical or inclined alignments [9, 10], anti-alignments [11], or random distributions of the QDs [12], having a strong effect on the optoelectronic behaviour [13]. The simulation of the strain–stress fields in a semiconductor material in order to predict the location of stacked nearly QDs lead to a better understanding of the behaviour of these complex

nanostructures. The finite elements method (FEM) is a widespread tool to calculate the strain and stress fields in semiconductor nanostructures, and it has been used in the study of QDs [11, 14, 15], QRings [16], or QWires [17]. In order to obtain reliable predictions by FEM, the simulations should be based in experimental composition data, because of the large impact of the concentration profile of the QD systems in the strain of the structure [18]. However, because of the difficulties in obtaining three-dimensional (3D) composition data with atomic resolution, many authors use theoretical compositions [11, 19], or two-dimensional (2D) experimental composition data (obtained by electron energy loss spectroscopy [20] or extrapolating composition concentration profiles measured by the lattice fringe analysis technique [21]). This makes a direct correlation between the predictions and the experimental results unfeasible, and prevents from verifying the accuracy of FEM in predicting the nucleation sites of QDs. To solve this, 3D composition data with atomic resolution should be collected. One of the most powerful techniques to obtain 3D composition data is atom probe tomography (APT).

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