Surface Roughness Changes Induced by Stoichiometric Deviation in Ambient Phase for Two-Component Semiconductor Crystals

2020

Sci Rep

Self Cite

the crossover from a Berezinskii-Kosterlitz-thouless (BKt) rough surface to a Kardar-parisi-Zhang (KpZ) rough surface on a vicinal surface is studied using the Monte carlo method in the non-equilibrium steady state in order to address discrepancies between theoretical results and experiments. the model used is a restricted solid-on-solid model with a discrete Hamiltonian without surface or volume diffusion (interface limited growth/recession). The temperature, driving force for growth, system size, and surface slope dependences of the surface width are calculated for vicinal surfaces tilted between the (001) and (111) surfaces. The surface velocity, kinetic coefficient of the surface, and mean height of the locally merged steps are also calculated. In contrast to the accepted theory for (2 + 1) surfaces, we found that the crossover point from a BKT (logarithmic) rough surface to a KPZ (algebraic) rough surface is different from the kinetic roughening point for the (001) surface. the driving force for crystal growth was found to be a relevant parameter for determining whether the system is in the BKT class or the KPZ class. It was also determined that ad-atoms, ad-holes, islands, and negative-islands block surface fluctuations, which contributes to making a BKT-rough surface.

Section: Resultscontrasting

confidence: 86%

Crossover from BKT-rough to KPZ-rough surfaces for interface-limited crystal growth/recession

2020

Sci Rep

Self Cite

“…Figure 4 (a) shows the results at equilibrium. In contrast to the two-component system of our previous work at equilibrium 55 , the linearity of the obtained data is high. This indicates that the elementary steps are well separated and the intervals between kinks are small relative to the system size.…”

Section: Dependencecontrasting

confidence: 86%

Crossover from BKT-Rough to KPZ-Rough Surfaces for Interface-Limited Crystal Growth/Recession

2020

Preprint

Self Cite

The crossover from a Berezinskii-Kosterlitz-Thouless (BKT) rough surface to a Kardar-Parisi-Zhang (KPZ) rough surface on a vicinal surface is studied using the Monte Carlo method in the non-equilibrium steady state in order to address discrepancies between theoretical results and experiments. The model used is a restricted solid-on-solid (RSOS) model with a discrete Hamiltonian without surface or volume diffusion (interface limited growth/recession). The temperature, driving force for growth, system size, and surface slope dependences of the surface width are calculated for vicinal surfaces tilted between the (001) and ( 111) surfaces. The surface velocity, kinetic coefficient of the surface, and mean height of the locally merged steps are also calculated. In contrast to the accepted theory for (2+1) surfaces, we found that the crossover point from a BKT (logarithmic) rough surface to a KPZ (algebraic) rough surface is different from the kinetic roughening point for the (001) surface. The driving force for crystal growth was found to be a relevant parameter for determining whether the system is in the BKT class or the KPZ class. It was also determined that ad-atoms, ad-holes, islands, and negative-islands block surface fluctuations, which contributes to making a BKT-rough surface.

“…At non-equilibrium in the faceted-rough region, if we regard the amplitude as a local degree of roughness, we can explain the anisotropy of the local roughness of the faceted-rough surface. In the faceted-rough region, is 0.01–0.03, as seen from Table 2 , whereas for a non-faceted vicinal surface is 0.08 65 , 69 . This anisotropy in is consistent with the anisotropies which were phenomenologically assumed 47 – 49 .…”

Section: Discussionmentioning

confidence: 89%

“…Details of the Monte Carlo calculations are given in Ref. 69 . Figure 2 shows a snapshot of the vicinal surface.…”

Section: Methodsmentioning

confidence: 99%

“…The square of the surface width W for a tilted surface in the non-equilibrium steady state is defined by 69 where and represent a site on the surface along the and directions, respectively, is the time average, g is the determinant of the first fundamental quantity of a curved surface 25 , and is the tilt angle inclined towards the direction from the direction. The time average is taken over Monte Carlo steps per site (MCS/site), discarding the first MCS/site 69 .…”

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Faceted-rough surface with disassembling of macrosteps in nucleation-limited crystal growth

2021

Sci Rep

Self Cite

To clarify whether a surface can be rough with faceted macrosteps that maintain their shape on the surface, crystal surface roughness is studied by a Monte Carlo method for a nucleation-limited crystal-growth process. As a surface model, the restricted solid-on-solid (RSOS) model with point-contact-type step–step attraction (p-RSOS model) is adopted. At equilibrium and at sufficiently low temperatures, the vicinal surface of the p-RSOS model consists of faceted macrosteps with (111) side surfaces and smooth terraces with (001) surfaces (the step-faceting zone). We found that a surface with faceted macrosteps has an approximately self-affine-rough structure on a ‘faceted-rough surface’; the surface width is strongly divergent at the step-disassembling point, which is a characteristic driving force for crystal growth. A ‘faceted-rough surface’ is realized in the region between the step-disassembling point and a crossover point where the single nucleation growth changes to poly-nucleation growth.