Grain-boundary diffusion in thin films. II. Multiple grain boundaries and surface diffusion

Gilmer, George H.; Farrell, H. H.

doi:10.1063/1.322441

Cited by 76 publications

(33 citation statements)

References 7 publications

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“…The partial differential equation system can be solved by the method of finite differences, using explicit [35] or the alternating direction implicit [34] (ADI) schemes.…”

Section: Accepted Manuscriptmentioning

confidence: 99%

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Nanoscale diffusion in Pt/56Fe/57Fe thin-film system

et al. 2015

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Low-temperature diffusion of Fe in Pt/ 56 Fe/ 57 Fe thin films (grown on MgO (100) substrate) was investigated between 703 K and 813 K using secondary neutral mass spectrometry. The activation energy of the effective interdiffusion coefficients, evaluated by the -centre-gradient‖ method, is 1.53±0.25 eV reflecting a strong contribution from grain boundaries. This is also supported by the observed deep penetrations of Pt into the 56 Fe layer, from which the grain boundary diffusion coefficients for Pt in Fe were also estimated and 1.45±0.25 eV activation energy was obtained. A simple model, including the effect of grain boundaries to the overall intermixing at the original sharp interfaces in nanocrystalline films, is developed. This predicts that at short annealing times the grain boundary diffusion dominates, and bulk diffusion coefficients can be determined only in long time limit. At intermediate annealing times, when the grain boundaries are saturated but the bulk diffusion is still negligible, there are no changes in the composition profiles.This yields good qualitative agreement with the experimental data and offers explanation for the time and temperature dependence of the interdiffusion coefficients obtained in similar systems.

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“…The partial differential equation system can be solved by the method of finite differences, using explicit [35] or the alternating direction implicit [34] (ADI) schemes.…”

Section: Accepted Manuscriptmentioning

confidence: 99%

“…(3a) describes the volume diffusion in the grain, the eq. (3b) gives the time evolution of the concentration in the boundary slab [31,34]. Because of the regularly spaced GBs, the diffusion problem should be solved for the unit cell, (unit cell dimensions:…”

Section: Accepted M Manuscriptmentioning

confidence: 99%

Nanoscale diffusion in Pt/56Fe/57Fe thin-film system

et al. 2015

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“…The 2-dimensional analytical solution developed by Gilmer and Farrell for polycrystalline films was employed using a constant diffusant source, reflecting back surface, and isolated grain boundaries [7]. Using measured grain size distributions and grain boundary width, estimated from TEM analysis to be ~20Å, 3-dimensional CuIn(Se 1-y S y ) 2 alloy distributions were determined for individual grain sizes and integrated to generate compositionally broadened x-ray diffraction (112) line profiles.…”

Section: Equilibrium Thermochemistry and Diffusion Modelmentioning

confidence: 99%

Formation and analysis of graded CuIn(Se1−ySy)2 films

Engelmann¹,

McCandless

Birkmire

2001

Thin Solid Films

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“…The 2-dimensional analytical solution developed by Gilmer and Farrell for polycrystalline films was employed using a constant diffusant source, reflecting back surface, and isolated grain boundaries [14]. Using measured grain size distributions and grain boundary width, estimated from TEM analysis to be ~20Å, 3-dimensional CuIn(Se 1-y S y ) 2 alloy distributions were determined for individual grain sizes and integrated to generate compositionally broadened x-ray diffraction (112) line profiles.…”

Section: Equilibrium Thermochemistry and Diffusion Modelmentioning

confidence: 99%

“…The diffusion process was modeled for simultaneous diffusion from source into grain and grain boundary and volume diffusion from grain boundary into the grain. The two dimensional solution for parallel grain boundaries in a sample of finite thickness proposed by Gilmer and Farrell [28] for Type B kinetics was adopted. The critical characteristic of Type B kinetics is that the grain boundary spacing is sufficient to allow them to be treated as isolated from one another.…”

Section: Quantitative Model Of Cdte/cds Interdiffusionmentioning

confidence: 99%

Optimization of Processing and Modeling Issues for Thin Film Solar Cell Devices Including Concepts for the Development of Polycrystalline Multijunctions Annual Subcontract Report, 24 August 1999 - 23 August 2000

Birkmire¹,

Phillips²,

Shafarman³

et al. 2001

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SUMMARYThe overall mission of the Institute of Energy Conversion (IEC) is the development of thin film photovoltaic cells, modules, and related manufacturing technology and the education of students and professionals in photovoltaic technology. The objectives of this 12 month NREL subcontract are to advance the state of the art and the acceptance of thin film PV solar cells in the areas of improved technology for thin film depositions, device fabrication, and material and device characterization and modeling, relating to solar cells based on CuInSe2 and its alloys, on doped and intrinsic microcrystalline Si films, and on CdTe. CuInSe 2 -BASED SOLAR CELLS In-line Evaporation of Cu(InGa)Se 2In-line evaporation is a potentially effective means to achieve the high rate uniform deposition necessary for commercial-scale manufacture of Cu(InGa)Se 2 modules. In this process, the substrate is linearly translated over thermal sources from which the elemental materials are evaporated.An in-line evaporation system for the deposition of Cu(InGa)Se 2 films has been put into operation at IEC. The system's performance in terms of uniform deposition over large areas at relatively high rates and in terms of device performance and reproducibility has been successfully demonstrated. The compositional uniformity across the 6-inch wide deposition zone is within the uncertainty limits of EDS measurements. A set of depositions with translation speeds ranging from 1 to 2.5 inches/min produced films with thicknesses from 2.1 to 0.9 µm. Devices from these runs had efficiencies from 13.2-14.5 %, for thickness > 1 µm, demonstrating the run-to-run reproducibility of the system. The best cell produced with Cu(InGa)Se 2 from this in-line system had 14.9% efficiency. Effect of Deposition Temperature on Cu(InGa)Se 2 Films and DevicesOne means to reduce manufacturing costs for thin film Cu(InGa)Se 2 is by reducing the substrate temperature at which the Cu(InGa)Se 2 layer is deposited. The effect of substrate temperature on the film grain size, morphology, and compositional uniformity and device performance of Cu(InGa)Se 2 deposited at 480°C was characterized and compared to previous results at 400°C and 550°C. At 480°C, the soda lime glass substrate is below the strain point of the glass, reducing handling problems.Cu(InGa)Se 2 films were deposited by multisource elemental evaporation with different deposition sequences to determine the effect of a Cu-rich growth step, i.e., deposition with the Cu molar flux greater than the sum of the In and Ga fluxes. The grain size was determined from atomic force microscopy images. The films deposited at 480°C have comparable grain size and morphology to those deposited at 550°C. However, V oc , FF, and efficiency of devices with films deposited at 550°C were greater. A Cu-rich growth step during the deposition does not affect the measured grain size or device performance at these temperatures. The films deposited at 400°Ciii have smaller grains and poorer device performance. At this lower temperature the Cu-...

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Grain-boundary diffusion in thin films. II. Multiple grain boundaries and surface diffusion

Cited by 76 publications

References 7 publications

Nanoscale diffusion in Pt/56Fe/57Fe thin-film system

Nanoscale diffusion in Pt/56Fe/57Fe thin-film system

Formation and analysis of graded CuIn(Se1−ySy)2 films

Optimization of Processing and Modeling Issues for Thin Film Solar Cell Devices Including Concepts for the Development of Polycrystalline Multijunctions Annual Subcontract Report, 24 August 1999 - 23 August 2000

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