GaAsN was grown by molecular beam epitaxy equipped with a radio frequency nitrogen plasma source. The N incorporation behaviors were investigated using a series of samples grown at different growth rates, As4/Ga ratios, and nitrogen fluxes within a growth temperature range from 420 to 560 °C. It was found that, for the GaAsN grown at higher growth rates (0.4–1.3 ML/s), the N concentration increased linearly following a decrease in growth rate, and kept independent of the arsenic pressure. For the GaAsN grown at lower growth rate (0.1–0.3 ML/s), the N concentration was significantly influenced by the arsenic pressure, and the increase in N concentration with decreasing growth rate follows a sublinear manner. We propose a model based on the incorporation competition of group V elements (N and As) under N underpressure and overpressure conditions, which can explain the different behaviors well.
Articles you may be interested inEffect of the growth temperature and the AlN mole fraction on In incorporation and properties of quaternary III-nitride layers grown by molecular beam epitaxy J. Appl. Phys. 104, 083510 (2008); 10.1063/1.2999564 Effect of N to Ga flux ratio on the GaN surface morphologies grown at high temperature by plasmaassisted molecular-beam epitaxy J. Appl. Phys. 95, 460 (2004); 10.1063/1.1634388 Modification of the microroughness of molecularbeam epitaxially grown GaAs/AlAs interfaces through changes in the growth temperatureThe effect of substrate growth temperature on deep levels in nAlxGa1−xAs grown by molecular beam epitaxy
We present a way to identify distortions of transparent micro-patterned substrates using a desktop document scanner and a set of image processing routines. The method requires neither expensive optical equipment nor precise positioning of the part. It is therefore ideally suited to rapid process monitoring. A 5000-dpi imagesetter is used to print a square reference grid of lines having a known pitch ~100 m. This reference pattern is used to produce a hard stamp that is subsequently embossed into a sheet of thermoplastic polymer. The pattern transferred to the polymer may include distortions resulting from contraction of the sheet after separation from the stamp. To measure these distortions, the embossed polymeric part is placed on a document scanner. The reference grid is laid on top of the part and rotated by hand until moiré fringes are seen. At least two scans are made, each with a different relative reference-part rotation. For each scan, the orientation of the part relative to the reference grid may be arbitrarily chosen within an allowable range of a few degrees. These orientations may be extracted from the captured images, and, together with the moiré fringes' orientations and spacings, provide enough information to obtain the part's distortions. Estimates of part strains may be improved, at the expense of measurement time, by capturing more images. The approach can detect isotropic shrinkage of the part with a strain resolution ~10 -3 .
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.