Articles you may be interested inImpact of varying buffer thickness generated strain and threading dislocations on the formation of plasma assisted MBE grown ultra-thin AlGaN/GaN heterostructure on silicon AIP Advances 5, 057149 (2015); 10.1063/1.4921757 Structural, morphological, and defect properties of metamorphic In0.7Ga0.3As/GaAs0.35Sb0.65 p-type tunnel field effect transistor structure grown by molecular beam epitaxy J. Vac. Sci. Technol. B 31, 041203 (2013); 10.1116/1.4812793 μm emission from type-I quantum wells grown on InAsxP1−x/InP metamorphic graded buffersStrain relaxation properties of InAs y P 1 − y metamorphic materials grown on InP substrates Impact of arsenic species ( As 2 ∕ As 4 ) on the relaxation and morphology of step-graded In As x P 1 − x on InP substrates J.In this study, metamorphic compositionally graded In x Al 1−x As layers grown on InP by molecular beam epitaxy with a final indium mole fraction of x = 1.0 ͑6.05 Å͒ are investigated. To examine the effects of relative growth temperature on strain relaxation and surface morphology at different stages of the buffer layer growth, a series of samples was produced with the indium mole fraction graded from x = 0.52 to x = 0.64, 0.79, and 1.0 with a constant grading rate. The high misfit dislocation velocity in this system allows the grading to be accomplished with a thin layer ͑ϳ1 m͒, complete strain relaxation and low threading dislocation densities. The evolution of the strain relaxation, threading dislocation density, and surface morphology were evaluated by triple axis x-ray diffraction, transmission electron microscopy (TEM), etch pit density (EPD), and atomic force microscopy. Higher growth temperature led to threading densities as low as 10 6 cm −2 , as measured by plan-view TEM and EPD. The final surface roughness was controlled by the growth temperature of a constant composition cap layer.

We have studied the dynamic phenomenon of Sn x Ge 1−x / Ge phase separation during deposition by molecular beam epitaxy on Ge͑001͒ substrates. Phase separation leads to the formation of direct band gap semiconductor nanowire arrays embedded in Ge oriented along the ͓001͔ growth direction. The effect of strain and composition on the periodicity were decoupled by growth on Ge͑001͒ and partially relaxed Si y Ge 1−y /Ge͑001͒ virtual substrates. The experimental results are compared with three linear instability models of strained film growth and find good agreement with only one of the models for phase separation during dynamic growth.

Nominally lattice-matched GaInAs layers grown by metal organic vapor phase epitaxy on InP substrates have been studied using high-resolution x-ray diffraction (HRXRD) to determine the growth conditions under which ordering is introduced. HRXRD provides an independent means to quantify the order parameter of semiconductor heterostructures as well as the ordering on different {111} planes, i.e., double variant ordering. This independent means to determine ordering provides for a better understanding of the effects of ordering on the electronic and optical properties. Double variant ordering was observed for epitaxial layers grown on exact (001) InP substrates, with an order parameter of about 0.1 in both variants. For substrates that were miscut by 6 degrees, single variant ordering was detected. In these cases, an order parameter as high as 0.66 was measured for certain growth conditions. The layers grown on vicinal substrates are all of high crystalline quality, those on (001) substrates exhibit some mosaic spread.

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