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The structural dynamics of an iodide layer adsorbed on Au(111) were investigated using X-ray photon correlation spectroscopy (XPCS), electrochemical scanning tunneling microscopy (STM), and time-resolved X-ray diffraction. At the adsorption equilibrium of iodide at a constant electrode potential, the STM images captured at regular intervals show the migration of atomic vacancy sites in the ordered adsorbed iodide layer. The results indicate that reversible adsorption/desorption and site conversion continuously occur at the equilibrium state. Although the transitions occur at various time scales according to the STM images, the time decay of the autocorrelation function at the specular position is estimated to be 127 s according to the XPCS measurement. The dynamics observed using XPCS suggest that the vertical relaxation of the surface layers is associated with the adsorption of iodide.

Using in situ synchrotron X-ray reciprocal space mapping, this study investigates the evolution of lattice deformations in the InGaAs/GaAs(1 1 1)A structure with or without a thin InAs layer grown by molecular beam epitaxy. During the initial growth phase, InGaAs directly grown on GaAs(1 1 1)A showed an anomalous lattice shrinkage along the c-axis, with no change in the indium composition. Conversely, the InGaAs grown on InAs/GaAs(1 1 1)A showed no initial lattice distortion, but a variable indium composition. The evolution of the diffraction peak broadening was also monitored. The results confirmed that the thin InAs layer effectively improved the crystal quality during the initial growth of InGaAs.

In this study, we analyzed the influence of indium supply on the growth dynamics of gold-catalyzed InGaAs nanowires by in situ synchrotron X-ray diffraction. A high In/Ga supply ratio results in strong size inhomogeneity of Au particles and interrupts the nanowire growth at a certain point of time. Based on the experimental results, we discussed the state of Au catalysts with high indium content during the nanowire growth. We found that a growth temperature below the eutectic temperature is essential to avoid the growth interruption and maintain the nanowire growth. The high In/Ga ratio necessitates accurate size control of Au particles before growth for further improvement of the nanowire growth.

Strain relaxation of InxGa1−xAs/GaAs(001) with systematically changed In content between x=0.23 and x=0.80 has been studied using in situ synchrotron X-ray diffraction during molecular beam epitaxy growth. Correlation between the In composition and the degree of relaxation in the InGaAs films was derived from the reciprocal space maps. While InGaAs with a uniform composition was grown in the regime of the two-dimensional growth, a separation of the In composition was observed for the InGaAs films grown in the Stranski-Krastanov mode.

In this work, in situ synchrotron X-ray diffraction reciprocal space mapping (RSM) measurements were carried out for the radio-frequency plasma-assisted molecular beam epitaxy (RF-MBE) growth of GaInN on GaN and InN layers, which were also grown by RF-MBE on commercialized GaN/c-sapphire templates. In situ XRD RSM measurements were performed using an MBE apparatus directly coupled to an X-ray diffractometer at the beamline of the synchrotron radiation facility SPring-8. It was observed in situ that both lattice relaxation and compositional pulling occurred during the initial growth stage, reducing the strain of GaInN on GaN and InN. Different initial growth behaviors of GaInN on GaN and InN were also observed from the results of the evolution of GaInN integrated peak intensities.

In situ synchrotron X-ray reciprocal space mapping was carried out to investigate the evolution of lattice strain and crystal structure of InGaN/GaN heterostructure nanowires grown by molecular beam epitaxy. At the beginning of the growth, the InGaN lattice was compressively strained to that of GaN, resulting in the pseudomorphic growth. This strain started to relax at a thickness of 3 nm and fully relaxed at 9 nm. Concomitantly, polytypes consisting of the zinc-blende and wurtzite phases were formed in InGaN., Compound Semiconductor Week 2019

The molecular beam epitaxial (MBE) growth of twenty-period InGaN/GaN multi-quantum-well (MQW) nanowires was investigated by in situ X-ray reciprocal space mapping (in situ RSM). The evolution of strain, composition, and their inhomogeneities during the growth significantly varied with increasing number of QWs. After the growth of the ninth QWs, InGaN was tensilely strained with poor crystalline quality as inferred from the diffraction peak position and shape. At the same time, another peak emerged at the higher indium composition, suggesting the segregation of InN in the MQW nanowires., Compound Semiconductor Week 2019

In recent years, graphene growth technology has been greatly progressed, and it is possible to grow graphene with millimeter-size single crystals using metal-catalysis CVD. However, the transfer process is unavoidably which largely deteriorates the graphene. We have proposed direct precipitation method of graphene using a W capping layer. The method does not only require a transfer process, but also the introduction of wrinkles will be suppressed by optimizing the cooling rate at the graphene precipitation. The growth conditions such as thickness of amorphous carbon, annealing temperature, cooling rate and crystallinity of Ni catalyst were systematically changed to study the mechanism of the precipitation method using the W cap layer. By the optimization of the conditions, wrinkle-free multilayer graphene with D/G ratio of less than 0.1 were successfully obtained directly on a sapphire substrate.

In situ X-ray diffraction measurement was performed to study the precipitation mechanism of graphene from Ni catalyst with and without Ti capping layer using X-ray beam from a synchrotron radiation facility. The graphene precipitated on the surface of the catalyst in the case without the Ti capping layer while it did at the interface between the catalyst and the sapphire substrate in the case with the Ti capping layer. Each process, such as graphene nucleation and precipitation was successfully monitored even though graphene precipitated under the metal catalyst. The detailed mechanisms for both cases were discussed using the experimental results. Consequently, the crystallization of the catalyst is found to effectively suppress the precipitation at low temperature, which is useful to improve the quality of the precipitated graphene. The adjustment of the amount of the carbons is another important factor to precisely control the precipitation because graphene also precipitates after the carbons saturate the catalyst.

In-situ X-ray diffraction was used to investigate initial stages of GaN growth on graphene-covered SiO2 substrates with or without AlN buffer layers by plasma-assisted molecular beam epitaxy. The in-plane lattice parameter of GaN remained almost constant during growth without AlN buffer layers, confirming weak interactions between GaN and graphene. On the substrate with AlN buffer layers, the GaN lattice parameter continuously changed from AlN value to GaN value, indicating that the AlN islands act as seeds for GaN growth. Besides, GaN has preferential orientations epitaxial to graphene. Graphene can be used as a template of GaN growth on amorphous substrates.

We carry out real-time in situ synchrotron X-ray diffraction on the growth of GaN and AlN on SiC(0001) substrate by molecular beam epitaxy. At the initial growth stage of GaN/SiC or AlN/SiC heterostructure, the epitaxial overlayer develops affected by defects with the strain interaction between SiC, eventually showing characteristic lattice deformations. GaN was almost relaxed at the initial stage, showing the transition of the growth mode from 3D to 2D at around 4 nm. In contrast, AlN coherently grow on SiC(0001) at the initial stage for 13 nm concomitantly showing lattice deformation with the beneath SiC, subsequently showing gradual lattice relaxation.

The evolution of polytypism during GaAs nanowire growth was investigated by in situ X-ray diffraction. The growth of nanowires was found to start with the formation of zincblende structure, followed by the growth of wurtzite structure. The growth process was well reproduced by a simulation based on a layer-by-layer nucleation model. The good agreement between the measured and simulated results confirms that nucleation costs higher energy for the stackings changing the crystal structure than for those conserving the preceding structure. The transition in prevalent structure can be accounted for by the change of local growth conditions related to the shape of a triple phase line rather than by the change in supersaturation level, which quickly reaches steady state after starting growth.

Synchrotron X-ray diffraction has been applied to the in situ monitoring of the molecular beam epitaxial growth of self-assembled InAs/GaAs(001) quantum dots (QDs). As well as the strain distribution inside QDs, the lateral and vertical size of QDs was determined as a function of growth time. In combination with post-growth atomic force microscopy, the evolution of the total volume of QDs was evaluated. It was found that the QD volume increases at a similar rate over the temperature range of 450–480 °C. A significant mass transport from the wetting layer and the substrate was confirmed.

In situ three-dimensional X-ray reciprocal space mapping ( in situ 3D-RSM) was employed for studying molecular beam epitaxial (MBE) growth of InGaAs multilayer structures on GaAs(0 0 1). Measuring the symmetric 004 diffraction allowed us to separately obtain film properties of individual layers and to track the real-time evolution of both residual strain and lattice tilting. In two-layer growth of InGaAs, significant plastic relaxation was observed during the upper layer growth, and its critical thickness was experimentally determined. At the same thickness, it was found that the direction of lattice tilting drastically changed. We discuss these features based on the Dunstan model and confirm that strain relaxation in the multilayer structure is induced by two kinds of dislocation motion (dislocation multiplication and the generation of dislocation half-loops).

Defect characterization in molecular beam epitaxial (MBE) compositionally-graded InxGa1-xAs layers on GaAs substrates consisting different thickness of overshooting (OS) layers was carried out using cathodoluminescence (CL) and transmission electron microscopy (TEM). We found that the thickness of the OS layer influences not only stress but also lattice defects generated in a top InGaAs layer. While the top InGaAs layer with a thin OS layer is under compression and has mainly threading dislocations, the top layer with a thick OS layer is under tension and exhibits inhomogeneous strain associating with phase separation. We will discuss the mechanisms of defect generation and their in-plane distribution based on strain relaxation at the top and OS layers. (© 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Multilayer structures comprised of a central layer of the binary transition metal pnictide MnSb and outer layers of standard semiconductors have been grown using molecular beam epitaxy (MBE). The growth of the GaAs overlayers was characterized using a combination of reflection high energy electron diffraction (RHEED) and in situ surface x-ray diffraction (SXRD). It was found that a GaAs overlayer can be grown via MBE onto a MnSb(1 101)/GaAs(001) virtual substrate. For both GaAs(111)A and InGaAs(111)A starting substrates, it was found that the GaAs overlayer altered the final strain state of the central MnSb layer causing a change from tensile strain to compressive strain in the out of plane direction.

In situ synchrotron X-ray diffraction studies during the growth of arsenide and nitride semiconductors are presented. The large penetration depth of X-rays was exploited for revealing structural changes at buried interfaces as well as near the surface. Experiments were performed at a synchrotron beamline, BL11XU, SPring-8, using a molecular-beam epitaxy chamber integrated with a high-precision X-ray diffractometer. A high-speed X-ray reciprocal space mapping technique was applied to a variety of heteroepitaxial systems including InGaAs on GaAs(001), InGaAs on GaAs(111)A and GaN on SiC(0001). Results showed that even layers as thick as 200 nm were not necessarily stable even after being buried under an overlayer but could undergo significant structural changes during growth.

This paper describes the development of a high-speed three-dimensional reciprocal-space mapping method designed for the real-time monitoring of the strain relaxation process during the growth of heterostructure semiconductors. Each three-dimensional map is obtained by combining a set of consecutive images, which are captured during the continuous rotation of the sample, and calculating the reciprocal-space coordinates from the detector coordinate system. To demonstrate the feasibility of this rapid mapping technique, the 022 asymmetric diffraction of an InGaAs/GaAs(001) thin film grown by molecular beam epitaxy was measured and the procedure for data calibration was examined. Subsequently, the proposed method was applied to real-time monitoring of the strain relaxation process during the growth of a thin-film heterostructure consisting of In0.07Ga0.93As and In0.18Ga0.82As layers consecutively deposited on GaAs(001). The time resolution of the measurement was 10 s. It was revealed that additional relaxation of the first In0.07Ga0.93As layer was induced by the growth of the second In0.18Ga0.82As layer within a short period of time corresponding to the deposition of only two monolayers of InGaAs.

The InSb(111)A surface is prepared by molecular beam epitaxy and investigated by reflection high-energy electron diffraction (RHEED). The complete two dimensional diffraction pattern is mapped out by azimuthal RHEED (ARHEED). Two reconstructions are identified and additionally a set of new symmetries is observed. At low temperature a 2 3 × 2 3 pattern is observed which changes to the (2 × 2) pattern at high temperature. In contrast to the GaSb(111)A surface the observed 2 3 × 2 3 structure is not stabilized by configurational entropy.

The effects of In incorporation on anisotropies in the strain relaxation mechanisms of InGaAs on GaAs systems are investigated using a three-dimensional reciprocal space mapping (3D-RSM) technique. Relaxation processes are classified as belonging to one of the following four phases: no relaxation, gradual relaxation, rapid relaxation, and relaxation saturation. Anisotropies appear in the gradual relaxation phase and almost disappear in the rapid relaxation phase. These anisotropies are enhanced by In content. When In content is low, both α- and β-misfit dislocations (MDs) are observed at the same thickness; the density of α-MDs increases more rapidly than that of β-MDs. When In content is high, only α-MDs appear in the gradual relaxation phase. These results suggest that In atoms prevent nucleation and/or gliding of β-MDs.

The structure of epitaxially grown Pr2O3 on Si(0?0?1) has been investigated by grazing incidence x-ray diffraction and x-ray reflectivity. We report experimental results from measurements made in situ, after growth, and during annealing to determine the stability of Pr2O3 at temperatures relevant for complementary metal oxide semiconductor (CMOS) processing. Pr6O11 is evaporated and converted to Pr2O3 using an effusion source operating at 1970 ?C. Two different phases of Pr2O3 have been identified in the as-grown films in addition to a silicate layer that forms upon nucleation at the Si interface. The cubic Pr2O3 nucleates as a single crystal and grows in greater proportion to the polycrystalline hexagonal Pr2O3. The crystal structure of the as-grown film is stable during annealing up to about 800 ?C at which point the Pr2O3 is consumed at the expense of the silicate phase.

Molecular-beam epitaxial growth of InAs/GaAs(0 0 1) quantum dots was investigated by grazing-incidence X-ray diffraction using a diffractometer directly coupled to an molecular-beam epitaxy (MBE) apparatus. The use of synchrotron radiation and a two-dimensional X-ray detector enabled reciprocal space mapping at a rate of 9.6 s per frame. The X-ray diffraction images revealed that the strain and shape of the quantum dots change significantly during the sequential growth process consisting of island formation, growth interruption and GaAs encapsulation.

The molecular-beam epitaxial growth processes of GaAs on Si(001) were investigated using in situ synchrotron X-ray diffraction. Three-dimensional X-ray intensity distributions around the Si and GaAs 022 Bragg points in reciprocal space were measured during growth using combination of an area detector and one-axis scans. During the initial stage of growth, the average radius of GaAs islands was found to follow a second power law function of the growth time, in accordance with the growth being limited by the binding of Ga with As at step edges. With increasing GaAs thickness, streaky scattering extending from the GaAs 022 peak in the 〈 111 〉 directions was observed, indicating the development of plane defects.

The GaAs(0 0 1)-( 2 × 4 ) reconstructed surface was investigated by in situ surface X-ray diffraction. X-ray diffraction patterns were measured with increasing substrate temperature within the β phase of GaAs(0 0 1)-( 2 × 4 ) in a constant As flux of 5 × 1 0 − 7 Torr. At relatively low temperatures up to 545 ∘C, the observed X-ray diffraction patterns agree well with the β 2( 2 × 4 ) surface. However, a different X-ray diffraction pattern was obtained at temperatures close to the α phase, while the 2 × 4 periodicity still persisted. This change is explained by partial As-dimer desorption which results in a mixture of the β 2( 2 × 4 ) and α 2( 2 × 4 ) structures.

An X-ray diffractometer connected with a molecular-beam epitaxy (MBE) system has been constructed for in situ studies on the growing surfaces of III–V compound semiconductors. This diffractometer is based on the (4+2) type, which has four axes for orienting the sample and two axes for positioning the detector. In addition, it is equipped with an axis for rotating the receiving slit about the normal of the slit plane to align the resolution of the receiving slit properly for the surface X-ray diffraction measurement. For the alignment of the sample and the entire setup with respect to the X-ray beam, an XYZ-stage and an adjustable base plate are available. X-rays enter and leave the chamber through two Be windows welded directly to the MBE chamber. A graphite sheet which can be heated up to 250°C is placed along the inside of the Be windows to protect the Be windows from being coated with evaporated materials. Preliminary data are presented to demonstrate the feasibility of static and dynamic measurements of growing surfaces using this instrument.

The effect of substrate orientation on strain relaxation mechanisms of an InGaAs layer grown on vicinal GaAs substrates was investigated by in situ X-ray diffraction (XRD). The crystallographic tilt and indium segregation in the InGaAs layer were altered depending on the miscut direction and angle. In the case of the substrate tilted 6° toward the [110] direction, one type of misfit dislocations was formed preferentially rather than other types, especially in the rapid relaxation phase. While in the case of the substrate tilted 6° toward the direction, no anisotropies during relaxation were observed. The present finding indicates that the appropriate use of vicinal substrates may lead to a novel method of improving the crystal quality of heterolayers.

The local structures around Nb and Pb in the prototypical relaxor ferroelectric Pb(Mg${}_{1/3}$Nb${}_{2/3}$)O${}_{3}$ (PMN) were investigated by x-ray fluorescence holography. The separate atomic images of nearest Pb around Nb revealed acute and obtuse rhombohedral structures of the crystal unit cells. The Pb-Pb correlated images showed a local structure of body-center-like $2{a}_{0}\ifmmode\times\else\texttimes\fi{}2{a}_{0}\ifmmode\times\else\texttimes\fi{}2{a}_{0}$ superlattice, proving a rigid three-dimensional network structural model combining the two kinds of rhombohedrons. The Pb atoms in the networks are positionally stable, while the other Pb atoms are fluctuating. This superstructure and the fluctuating Pb and Nb atoms are believed to play an important role in the relaxor behavior of PMN at the atomic level.

InAs nanowires that grow catalyst-free along the [111] crystallographic orientation are prone to wurtzite-zincblende polytypism, making the control of the crystal phase highly challenging. In this work, we explore the dynamic relation between the growth conditions and the structural composition of the nanowires using time-resolved X-ray scattering and diffraction measurements during the growth by molecular beam epitaxy. A spontaneous buildup of liquid indium is directly observed in the beginning of the growth process and associated with the simultaneous nucleation of InAs nanowires predominantly in the wurtzite phase. The highly arsenic-rich growth conditions that we used limited the existence of the liquid indium to a short time interval, which is defined as the nucleation phase. After their nucleation, the nanowires grow in the absence of liquid indium, and with a highly defective wurtzite structure. Complementary ex-situ diffuse X-ray scattering measurements and modeling revealed that this structural degradation is due to the formation of densely spaced stacking faults. Thus, high wurtzite phase purity is associated with the presence of liquid indium. This finding implies that pure wurtzite nanowires may be obtained only if the growth is performed under the continuous presence of liquid indium at the growth interface, that is, in the vapor-liquid-solid mode.

In situ X-ray reciprocal space mapping during InxGa1−xAs/GaAs(001) MBE growth is performed to investigate effects of substrate misorientations on crystallographic tilting. It was found that evolution of the crystallographic tilt for the InGaAs films is strongly dependent on both layer structures and substrate misorientations. We discuss these observations in terms of an asymmetric distribution of dislocations.

We have investigated the growth by molecular beam epitaxy (MBE) of GaAs on MnSb. MnSb epilayers on GaAs(111), GaAs(001) and In0.5Ga0.5As(111) of thickness ∼ 50 nm were used as substrates for GaAs films. The MBE growth of GaAs was monitored in situ using synchrotron X-ray diffraction and reflection high energy electron diffraction. We show data on strain relaxation and growth mode, and discuss the epitaxial relationship between GaAs(001) and MnSb(11‾01). Schematic of the molecular beam epitaxy/X-ray diffraction in situ experiment and typical 2D detector data, with GaAs(111) and MnSb(0001) diffraction features.

A molecular beam epitaxy (MBE) chamber dedicated to nitride growth was developed at the synchrotron radiation facility SPring-8. This chamber has two beryllium windows for incident and outgoing X-rays, and is directly connected to an X-ray diffractometer, enabling in situ synchrotron X-ray measurements during the nitride growth. Experimental results on initial growth dynamics in GaN/SiC, AlN/SiC, and InN/GaN heteroepitaxy were presented. We achieved high-speed and high-sensitivity reciprocal space mapping with a thickness resolution of atomic-layer scale. This in situ measurement using the high-brilliance synchrotron light source will be useful for evaluating structural variations in the initial growth stage of nitride semiconductors.

The formation and evolution of rotational twin (TW) domains introduced by a stacking fault during molecular-beam epitaxial growth of GaAs on Si (111) substrates were studied by in situ x-ray diffraction. To modify the volume ratio of TW to total GaAs domains, GaAs was deposited under high and low group V/group III (V/III) flux ratios. For low V/III, there was less nucleation of TW than normal growth (NG) domains, although the NG and TW growth rates were similar. For high V/III, the NG and TW growth rates varied until a few GaAs monolayers were deposited; the mean TW domain size was smaller for all film thicknesses.

The polytypism of GaAs nanowires was investigated by in situ X-ray diffraction under different growth conditions. The growth of nanowires was found to start with the formation of the zincblende structure, followed by the growth of the wurtzite structure. The observed growth process of nanowires was well reproduced by simulations based on a layer-by-layer nucleation model. At a low growth temperature and a high growth rate, stacking faults were found to be frequently introduced owing to the reduction in energy barrier. As a result, the zincblend and wurtzite segments in nanowires were highly fragmented and the wurtzite structure was formed in the early stage of growth.

We report an anomalous lattice deformation of GaN layers grown on SiC(0001) by molecular beam epitaxy. The evolution of the lattice parameters during the growth of the GaN layers was measured by in situ synchrotron X-ray diffraction. The lattice parameters in the directions parallel and normal to the surface showed significant deviation from the elastic strains expected for lattice-mismatched films on substrates up to a thickness of 10 nm. The observed lattice deformation was well explained by the incorporation of hydrostatic strains due to point defects. The results indicate that the control of point defects in the initial stage of growth is important for fabricating GaN-based optoelectronic devices.

The structure of thin Pd films grown on Au(111) and Au(001) electrodes in a solution containing PdCl(4)(2 -) and SO(4)(2 -) has been investigated by surface x-ray scattering. This technique provided structural information on the Pd films in the lateral direction as well as in the surface normal direction. Comparison of Pd/Au(111) and Pd/Au(001) growth modes shows similarity in the first layer deposition. On Au(111) and Au(001) substrates, Pd follows the crystal structure of the substrates and forms a pseudomorphic monolayer. Beyond 2 ML, however, Pd films grown on Au(111) are relaxed, although there are still pseudomorphic layers at the interface. In contrast, Pd films on Au(001) continue to grow pseudomorphically over 10 ML. The difference in the growth mode between (111) and (001) surfaces is not ascribable only to anisotropy in the elasticity of the film. The relationship between a growing surface and an allowed gliding plane in misfit dislocations is presented as a crucial factor determining the critical thickness of the film.

The in situ X-ray reciprocal space mapping (in situ RSM) of symmetric diffraction measurements during lattice-mismatched InGaAs/GaAs(001) growth were performed to investigate the strain relaxation mechanisms. The evolution of the residual strain and crystal quality were obtained as a function of InGaAs film thickness. Based on the results, the correlation between the strain relaxation and the dislocations during the film growth were evaluated. As a result, film thickness ranges with different relaxation mechanisms were classified, and dominant dislocation behavior in each phase were deduced. From the data obtained in in situ measurements, the quantitative strain relaxation models were proposed based on a dislocation kinetic model developed by Dodson and Tsao. Good agreement between the in situ data and the model ensured the validity of the dominant dislocation behavior deduced from the present study.

In situ real-time x-ray diffraction measurements during In 0.12 Ga 0.88 As/GaAs(001) epitaxial growth are performed for the first time to understand the strain relaxation mechanisms in a lattice-mismatched system. The reciprocal space maps of 004 diffractions are obtained, and allow us to evaluate the evolution of residual strain and crystal quality simultaneously as a function of layer thickness. In the time evolution, we have classified five thickness ranges, and deduced the dominant dislocation behavior in each phase.

The evolution of strain inside InAs/GaAs(001) quantum dots during annealing after deposition was studied by in situ grazing‐incidence X‐ray diffraction. The use of synchrotron radiation and two‐dimensional detector enabled measurements at a temporal resolution of 9.6 s. The temperature dependence of the structural change during annealing can be interpreted in terms of the miscibility of InAs and GaAs.

Direct measurements on the growth of InAs quantum dots (QDs) and various cap layers during molecular beam epitaxy are performed by in situ X-ray diffraction (XRD). The evolution of strain induced both in the QDs and cap layers during capping is discussed based on the XRD intensity transients obtained at various lattice constants. Transients with different features are observed from those obtained during InGaAs and GaAs capping. The difference observed is attributed to In-Ga intermixing between the QDs and the cap layer under limited supply of In. Photoluminescence (PL) wavelength can be tuned by controlling the intermixing, which affects both the strain induced in the QDs and the barrier heights. The PL wavelength also varies with the cap layer thickness. A large redshift occurs by reducing the cap thickness. The in situ XRD observation reveals that this is a result of reduced strain. We demonstrate how such information about strain can be applied for designing and preparing novel device structures.