In situ study of the kinetics of displacement of growth steps on {010} faces of potassium acid phthalate single crystals grown from aqueous solutions

Sangwal, K.; Wójcik, Katarzyna; Borc, J.

doi:10.1002/crat.200310083

Cited by 7 publications

(5 citation statements)

References 49 publications

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“…The experiments were carried out in pure solutions and in solutions containing different concentrations of Cu(II), Cr(III), Fe(III) and Mn(II) impurities up to 0.15 mole fraction with respect to ammonium oxalate solute. As reported earlier [17], the lowest limit of the height of steps visible in the experiments was about 100 nm. [17].…”

Section: Methodsmentioning

confidence: 84%

“…As reported earlier [17], the lowest limit of the height of steps visible in the experiments was about 100 nm. [17]. The dependence of the mean velocity v of different steps and the mean velocity v of movement of all steps in an experiment on temperature T of pure solution is shown in figure 4.…”

Section: Methodsmentioning

confidence: 84%

“…Our experimental set-up for the study of the kinetics of movement of layers was essentially the same as that used for the investigation of movement of layers on the {010} faces of potassium acid phthalate single crystals [17]. The experimental set-up is composed of two round-bottomed flasks F 1 and F 2 containing ammonium oxalate solution at temperatures T 1 and T 2 , respectively, and a specially-designed growth cell in which crystal seed was properly mounted for the observation of growth and dissolution steps at a pre-defined temperature T c .…”

Section: Methodsmentioning

confidence: 99%

“…The stronger the adsorption of an impurity, the higher is fluctuation in growth velocity v and kinetic coefficient β. The process involved in the fluctuation of step velocities has been discussed in detail earlier for impurity-free system [2,17]. Feature 4 is probably associated with the fact that growth is controlled by the attachment of growth units in the presence of impurity species but dissolution is controlled by volume diffusion.…”

Section: Mn(c O )mentioning

confidence: 98%

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In situ study of growth and dissolution kinetics of ammonium oxalate monohydrate single crystals from aqueous solutions containing cationic impurities

Sangwal

Wójcik

Borc

2007

Cryst. Res. Technol.

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The results of an in situ investigation of the effect of four different bi-and trivalent cations (Fe(III), Cu(II), Mn(II) and Cr(III)) on the displacement velocity of individual growth steps on the (110) face of ammonium oxalate monohydrate crystals as a function of supersaturation are described and discussed. It was observed that: (1) at a particular temperature of pure solutions and solutions containing impurities, the velocity v of movement of the [110] growth steps is always greater than that of the [111] steps, (2) fluctuations in the velocity of individual growth steps occur in all solutions containing similar concentrations of different impurities, (3) the value of kinetic coefficient β for growth steps decreases with an increase in the concentration c i of Cu(II) impurity, but that for dissolution steps does not depend on c i ; moreover, the value of kinetic coefficient β for growth steps is higher than that of dissolution steps, and (4) in the presence of Mn(II) and Cr(III) impurities, the kinetic coefficient β for dissolution steps is several times greater than that for growth steps. The results are explained from the standpoint of Kubota-Mullin model of adsorption of impurities at kinks in the steps and the stability of dominating complexes present in solutions. Analysis of the results revealed that: (1) the effectiveness of different impurities in inhibiting growth increases in the order: Fe(III), Cu(II), Mn(II), and Cr(III), and this behavior is directly connected with the stability and chemical constitution of dominating complexes in saturated solutions, (2) fluctuations in the velocity of growth steps is associated with the effectiveness of an impurity for adsorption; the stronger the adsorption of an impurity, the higher is the fluctuation in step velocity v, and (3) depending on the nature of the impurity, the kinetic coefficient for the dissolution steps can remain unchanged or can be higher than that of the growth steps.

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Section: Methodsmentioning

confidence: 84%

Section: Methodsmentioning

confidence: 84%

Section: Methodsmentioning

confidence: 99%

Section: Mn(c O )mentioning

confidence: 98%

See 2 more Smart Citations

In situ study of growth and dissolution kinetics of ammonium oxalate monohydrate single crystals from aqueous solutions containing cationic impurities

Sangwal

Wójcik

Borc

2007

Cryst. Res. Technol.

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“…The relationship between tangential velocity of step and kinetic coefficient is:

v = ω β (C - C_{normale})

where

ω = 3.35 \times 10^{- 22} c m^{3}

is the volume of single ZTS molecule, actual concentration

C = 8.1 \times 10^{19} normalc m^{- 3}

, and equilibrium concentration

C_{normale} = 7.7 \times 10^{19} normalc m^{- 3}

. The activation energy E that a growth unit needs to enter a growing step can be calculated by :

β = h υ exp (- E / k T)

where h is step height (1.1 nm for nucleus N 1 and N 5 ), k is the Boltzmann's constant, T is the Kelvin temperature and υ is the atom vibration frequency evaluated as υ = 10 13 s −1 .…”

Section: Resultsmentioning

confidence: 99%

In situ atomic force microscopy studies of growth mechanisms and surface morphology of zinc thiourea sulfate crystals

Song

Cao

et al. 2015

Crystal Research and Technology

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In situ atomic force microscopy (AFM) has been utilized in studies of the growth mechanism on the (100) face of zinc tris (thiourea) sulphate (ZTS) crystals growing from solution. The growth on the (100) face of pure ZTS crystal is mainly controlled by two dimensional (2D) nucleation mechanisms, under which the hillock is formed through layer‐by‐layer growth. It is easier to form 2D nuclei at edge dislocation and the apex of steps. The growth of 2D nucleus is in accord with nucleation‐spreading mode. The growth rate along the 〈010〉 direction is faster than that along 〈001〉 direction, both of which increase firstly and then decrease with the spread of nucleus. The kinetic coefficients of one nucleus have been roughly estimated to be 3.6 × 10−4 cm/s and 1.8 × 10−4 cm/s in two directions, while the activation energy E was calculated to be 53.7 kJ/mol and 55.4 kJ/mol, respectively. The 2D nuclei can be generated under lower supersaturation with the addition of EDTA. If there are several hillocks growing together, step bunches will form when the steps moving in the same direction meet each other, while the meeting of steps that move in the inverse direction will result in the separation of steps. The ability of nucleation of edge dislocation outcrops are different even they are close to each other on the same surface. When the nucleus was generated at the edge dislocation sites, it cannot spread speedily until finishes an “incubation period”. Moreover, the detour of microsteps was observed due to the existence of pits. If the microcrystals attached on the surface block the step advancement, or leave the surface or are covered by the macrosteps, the pits are formed. If the macrosteps advanced across the pits, the pits will be covered and the liquid inclusions may form. However, if the microcrystal forming in the pit grow up and expose on the surface, the pit will not be covered by macrosteps. The formation of solid inclusions may be caused by the microcrystals being embedded into the single steps which move layer‐by‐layer.

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Habit modification and improvement in properties of potassium hydrogen phthalate (KAP) crystals doped with metal ions

Geetha

Perumal

Babu³

et al. 2006

Cryst. Res. Technol.

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Potassium hydrogen phthalate (KAP) single crystals were grown by slow evaporation and slow cooling techniques. The growth procedure like temperature cooling rate, evaporation rate, solution pH, concentration of the solute, supersaturation ratio etc., has been varied to have optically transparent crystals. Efforts were made to dope the KAP crystals with rubidium, sodium and lithium ions. The dopant concentration has been varied from 0.01 to 10 mole percent. Good quality single crystals were grown with different concentrations of dopants in the mother phase. Depending on the concentration of the dopants and the solution pH value, there is modification of habit. Rubidium ions very much improve the growth on the prismatic faces. The transparency of the crystals is improved with rubidium and sodium doping. The role of the dopants on the non-linear optical performance of KAP indicates better efficiency for doped crystals. The grown crystals were characterized with XRD, FT-IR, chemical etching, Vickers microhardness and SHG measurements. The influence of the dopants on the optical, chemical, structural, mechanical and other properties of the KAP crystals was analysed.

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In situ study of the kinetics of displacement of growth steps on {010} faces of potassium acid phthalate single crystals grown from aqueous solutions

Cited by 7 publications

References 49 publications

In situ study of growth and dissolution kinetics of ammonium oxalate monohydrate single crystals from aqueous solutions containing cationic impurities

In situ study of growth and dissolution kinetics of ammonium oxalate monohydrate single crystals from aqueous solutions containing cationic impurities

In situ atomic force microscopy studies of growth mechanisms and surface morphology of zinc thiourea sulfate crystals

Habit modification and improvement in properties of potassium hydrogen phthalate (KAP) crystals doped with metal ions

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