Effect of immobile impurities on motion of steps on a vicinal face

Sato, Masahide

doi:10.1103/physreve.84.061604

Cited by 5 publications

(3 citation statements)

References 13 publications

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“…In our simulation, we distinguish adatoms, impurities, solid atoms, and impurities incorporated in solid [16,17]. The elementary processes we take into account are the migration of adatoms, the evaporation of both adatoms and impurities, and the solidification of the adatoms attaching to steps.…”

Section: Modelmentioning

confidence: 99%

“…This may be caused by the effect of the surface diffusion field: mobile molecules migrate on crystal surface more slowly than in solution and are immobilized after finding stable sites. Since the surface diffusion process may be important even in the case of growth from solution, we considered vapor growth and studied the effect of the surface diffusion field of adatoms on the step bunching induced by immobile impurities [16,17]. For the materials such as proteins, it is difficult to prepare specimens of high purity.…”

Section: Introductionmentioning

confidence: 99%

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Effect of evaporation on step bunching induced by impurities

Sato

2018

Phys. Rev. E

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In this paper, we study the effect of the evaporation of adatoms and impurities on the step bunching induced by impurity. Keeping the ratio of the impingement rate of impurities F_{imp} to that of atoms F constant, we carry out Monte Carlo simulation. In the system with the evaporation of impurities, the growth rate of vicinal face R is proportional to F. This relation is the same as that without the evaporation of impurities. When F is small, the vicinal face is unstable. Compared with the system without the evaporation of impurities, the effect of impurities is weakened. In our simulation, step pairing occurs but large bunches are not formed. When we take account of the evaporation of both impurities and adatoms, the vicinal face grows when F is larger than the equilibrium value F_{eq}. R is not proportional to (F-F_{eq}) and large bunches are formed when F is small. In this paper, we also show how the impurity density on surface σ_{imp} and that incorporated in solid ρ_{imp} are related to the formation of step bunches.

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Section: Modelmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Effect of evaporation on step bunching induced by impurities

Sato

2018

Phys. Rev. E

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“…In order to make progress on the issue, we performed kinetic Monte Carlo (kMC) simulations using a solid-on-solid scheme by which we can inspect the system at the required atomic level (Figure ). Our methodology is complementary to more coarse-grained semimicroscopic models that have been successfully employed to describe the coarsening behavior at long time scales and the emergence of steady states. − Of particular relevance is the work by Ranganathan and Weeks , who have used a terrace-step-kink model to investigate the growth recovery of pinned steps. Their model elegantly captures the general experimental trends but does not provide a detailed view on the physics of step cooperativity at the nanoscopic scale discussed above.…”

Section: Introductionmentioning

confidence: 99%

Mineral Growth beyond the Limits of Impurity Poisoning

Sleutel

Lutsko

Driessche

2017

Crystal Growth & Design

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More often than not, minerals formed in nature are grown at low supersaturation and from sources that are impure with respect to the crystals’ main building blocks. Quite paradoxically, these conditions are in conflict with the established crystal growth theories that focus on the interplay between the crystal interface and impurities that are present in the growth medium. These theories predict a kinetic dead zone for the cases where low purity is combined with weak driving forces. Hints toward reconciling this apparent disparity have been given by the observation that a specific class of steps, so-called macrosteps, can circumvent the debilitating kinetic effects of impurities in ways that up until now are poorly understood. In this contribution, we examine the mechanism of crystal growth by means of kinetic Monte Carlo simulation at conditions close to impurity-induced kinetic arrest. In agreement with previous reports, we show that as a result of impurity binding to the crystal surface, steps spontaneously group into bunches and later condense into macrosteps. A kinetic analysis demonstrates that these macrosteps are able to evade crystal growth cessation under conditions where single steps are firmly pinned. We identify the mechanism of interstep cooperativity which leads to cessation evasion by macrosteps and demonstrate that it applies to a range of supersaturation and impurity concentration values. On the basis of these findings, we present a model that explains how minerals can grow from mother liquor solutions that would otherwise seem to be nonconducive to crystal growth.

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Impurity-induced Step Pinning and Recovery in MOVPE-grown (100) β-Ga2O3 Film: The Influence of Ga supersaturation

Chou,

Rehm,

Anooz

et al. 2024

Preprint

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This study focuses on the impact of high-doping impurities (> 1018 cm− 3) on the morphology of homoepitaxially grown (100) 4°off β-Ga2O3 film, as well as incorporating insights from the Cabrera-Vermilyea model (C-V model). Using atomic force microscopy (AFM) imaging, we reveal that under low supersaturation conditions, dopant-induced impurities lead to irregular step formation and growth stalling, inducing the step-bunching formation consistent with C-V model predictions. Conversely, higher supersaturation conditions restore desired step-flow morphology, resembling low-impurity growth states. It is also shown that the step-bunching formed under lower supersaturation conditions and high impurity concentration might induce unwanted structural defects and compensate the free carriers. These findings underscore the delicate interplay between dopant concentrations, growth morphology, and supersaturation in MOVPE-grown (100) β-Ga2O3 films, providing a comprehensive understanding for optimizing their electrical properties with respect to power electronics applications.

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Effect of immobile impurities on motion of steps on a vicinal face

Cited by 5 publications

References 13 publications

Effect of evaporation on step bunching induced by impurities

Effect of evaporation on step bunching induced by impurities

Mineral Growth beyond the Limits of Impurity Poisoning

Impurity-induced Step Pinning and Recovery in MOVPE-grown (100) β-Ga2O3 Film: The Influence of Ga supersaturation

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