Phase-field simulations of GaN/InGaN quantum dot growth by selective area epitaxy

Aagesen, Larry K.; Lee, L.K.; Ku, Pei-Cheng; Thornton, Katsuyo

doi:10.1016/j.jcrysgro.2012.08.042

Cited by 9 publications

(23 citation statements)

References 56 publications

(61 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Therefore, k dep and k dis are similar to the orientation-dependent growth velocity in Ref. 20, except that the growth velocity in this model also depends on the other variables in Eq. 2.…”

Section: Modelsupporting

confidence: 55%

“…The evolution of the Mg deposit is modeled using a phase field approach similar to that used to model InGaN quantum dot growth by selective area epitaxy. 20,21 As in many previous publications, …”

Section: Modelmentioning

confidence: 60%

“…In Ref. 20, the boundary condition between the growing quantum dot and the immobile substrate was applied using the smoothed boundary method (SBM). The SBM is designed to restrict the solution of an equation to a subdomain within the larger computational domain and to efficiently apply boundary conditions along the boundary of that subdomain.…”

Section: Computational Methods and Numerical Parametersmentioning

confidence: 99%

“…As in Ref. 20, the SBM is used to enforce a no-flux boundary condition along the substrate interface and to enforce a contact angle boundary condition, θ, at the triple phase boundary between the electrolyte, the deposit, and the substrate. The contact angle is determined by the balance of interfacial tensions between the three phases.…”

Section: Computational Methods and Numerical Parametersmentioning

confidence: 99%

See 3 more Smart Citations

Computational Examination of Orientation-Dependent Morphological Evolution during the Electrodeposition and Electrodissolution of Magnesium

DeWitt

Hahn

Zavadil

et al. 2015

J. Electrochem. Soc.

Self Cite

View full text Add to dashboard Cite

A new model of electrodeposition and electrodissolution is developed and applied to the evolution of Mg deposits during anode cycling. The model captures Butler-Volmer kinetics, facet evolution, the spatially varying potential in the electrolyte, and the time-dependent electrolyte concentration. The model utilizes a diffuse interface approach, employing the phase field and smoothed boundary methods. Scanning electron microscope (SEM) images of magnesium deposited on a gold substrate show the formation of faceted deposits, often in the form of hexagonal prisms. Orientation-dependent reaction rate coefficients were parameterized using the experimental SEM images. Three-dimensional simulations of the growth of magnesium deposits yield deposit morphologies consistent with the experimental results. The simulations predict that the deposits become narrower and taller as the current density increases due to the depletion of the electrolyte concentration near the sides of the deposits. Increasing the distance between the deposits leads to increased depletion of the electrolyte surrounding the deposit. Two models relating the orientation-dependence of the deposition and dissolution reactions are presented. The morphology of the Mg deposit after one deposition-dissolution cycle is significantly different between the two orientation-dependence models, providing testable predictions that suggest the underlying physical mechanisms governing morphology evolution during deposition and dissolution. Magnesium batteries have garnered substantial attention as a successor to Li-ion batteries due to their potential for high energy density and safe operation.1-3 Metallic Mg anodes provide a substantially higher specific volumetric capacity (3833 mA h/cm 3 ) than either Ligraphite anodes (760 mA h/cm 3 ) or metallic Li anodes (2046 mA h/cm 3 ). 2 Furthermore, unlike metallic Li anodes, 5 metallic Mg anodes can be cycled without the formation of dendrites. 4 Dendrite growth poses a hazard because dendrites can grow across the separator to the cathode and short the battery, leading to thermal runaway. 5,6 Instead of forming dendrites, metallic Mg anodes form compact, faceted films, practically eliminating this risk. 4 Understanding the evolution of this Mg film during cycling is a critical factor in the development of high-performance magnesium batteries. 7Although the development of electrolytes for the efficient and reversible deposition and dissolution of Mg has been pursued extensively (see Refs. 1 and 2 for comprehensive reviews on this topic), much less attention has been given to the morphological evolution of the Mg deposits during cycling. SEM and AFM images of the Mg film typically show a highly faceted film with grains on the order of 1 μm in width. [8][9][10][11] However, other morphologies with either larger 10 or smaller 12,13 features have also been observed. The most comprehensive examination of the morphology of electrodeposited Mg was conducted by Matsui, 4 who examined the morphology of 1 C/cm 2 of Mg deposited at 0.5...

show abstract

“…Therefore, k dep and k dis are similar to the orientation-dependent growth velocity in Ref. 20, except that the growth velocity in this model also depends on the other variables in Eq. 2.…”

Section: Modelsupporting

confidence: 55%

Section: Modelmentioning

confidence: 60%

Section: Computational Methods and Numerical Parametersmentioning

confidence: 99%

Section: Computational Methods and Numerical Parametersmentioning

confidence: 99%

See 2 more Smart Citations

Computational Examination of Orientation-Dependent Morphological Evolution during the Electrodeposition and Electrodissolution of Magnesium

DeWitt

Hahn

Zavadil

et al. 2015

J. Electrochem. Soc.

Self Cite

View full text Add to dashboard Cite

show abstract

“…18 Periodic arrays of circular mask openings have been used to produce microor nano-dots for applications such as LEDs and energy selective contacts for hot carrier solar cells. [19][20][21][22][23][24][25][26][27][28] For LED applications, micro-ring emitters can give nearly double the efficiency of micro-dot emitters. 29 Therefore, micro-ring emitters have been grown from ring-shaped mask openings using selective area epitaxy for this application.…”

Section: Introductionmentioning

confidence: 99%

Phase-field simulations of GaN growth by selective area epitaxy from complex mask geometries

Aagesen

Coltrin

Han

et al. 2015

Journal of Applied Physics

View full text Add to dashboard Cite

Articles you may be interested inGrowth kinetics and mass transport mechanisms of GaN columns by selective area metal organic vapor phase epitaxy Three-dimensional phase-field simulations of GaN growth by selective area epitaxy were performed. The model includes a crystallographic-orientation-dependent deposition rate and arbitrarily complex mask geometries. The orientation-dependent deposition rate can be determined from experimental measurements of the relative growth rates of low-index crystallographic facets. Growth on various complex mask geometries was simulated on both c-plane and a-plane template layers. Agreement was observed between simulations and experiment, including complex phenomena occurring at the intersections between facets. The sources of the discrepancies between simulated and experimental morphologies were also investigated. The model provides a route to optimize masks and processing conditions during materials synthesis for solar cells, light-emitting diodes, and other electronic and opto-electronic applications. V C 2015 AIP Publishing LLC.

show abstract

Origin of broad luminescence from site‐controlled InGaN nanodots fabricated by selective‐area epitaxy

Lee

Aagesen

Thornton

et al. 2014

Physica Status Solidi (a)

Self Cite

View full text Add to dashboard Cite

We investigated the origin of broad luminescence observed from an array of site-controlled InGaN nanodots grown by selective area epitaxy (SAE). Epitaxially grown site-controlled nanodots with lateral dimensions <50 nm and an array density of 10 10 cm À2 have been studied. During the nanoscale SAE, incorporation of adatoms from the SiO 2 mask has greater relative importance, resulting in a non-uniform growth profile. This non-uniform growth profile leads to significant broadening of the InGaN nano-heterostructure luminescence. Later in the SAE process, an orientation-dependent growth rate coalesces various crystal planes and transforms these nanostructures into a more uniform array.1 Introduction III-nitride nanostructures possess unique properties, such as a wide tuning range for the emission wavelength [1, 2] large exciton binding energy (!26 meV in bulk) [3,4], and robust spin coherence [5], making them particularly attractive for applications in nanophotonics [6,7], spintronics [5,8], and quantum information processing [7,9]. In many of these applications, it is critical to be able to control the dimension and location of the nanostructures. For example, exciton-cavity coupling requires the precise placement of a single quantum dot heterostructure at the anti-node of an optical cavity [10]. To date, most of the III-nitride nanostructures have been fabricated by the self-assembled Stranski-Krastanow (SK) growth [11], which does not enforce control over the structures' position or dimension, demotivating their practical use on the device level. In recent years, selective area epitaxy (SAE) using metal-organic chemical vapor deposition (MOCVD) has been proven to be feasible for the fabrication of a variety of site-controlled III-nitride nanostructures, such as nanowires [12] and nanodots [2,[13][14][15][16][17][18]. During SAE, the morphology of the three-dimensional epistructure grown within the mask opening evolves according to the growth dynamics [12,19], source supply mechanisms [20,21], and growth rate anisotropy [22,23]. Because optical properties of III-nitride heterostructures strongly

show abstract

Phase-field simulations of GaN/InGaN quantum dot growth by selective area epitaxy

Cited by 9 publications

References 56 publications

Computational Examination of Orientation-Dependent Morphological Evolution during the Electrodeposition and Electrodissolution of Magnesium

Computational Examination of Orientation-Dependent Morphological Evolution during the Electrodeposition and Electrodissolution of Magnesium

Phase-field simulations of GaN growth by selective area epitaxy from complex mask geometries

Origin of broad luminescence from site‐controlled InGaN nanodots fabricated by selective‐area epitaxy

Contact Info

Product

Resources

About