Chemical diffusion of copper in lead telluride

Schneider, Christian; Schichtel, Patrick; Mogwitz, Boris; Rohnke, Marcus; Janek, Jürgen

doi:10.1016/j.ssi.2017.02.012

Cited by 8 publications

(4 citation statements)

References 30 publications

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“…This feature can affect the long‐term stability of compounds used in real applications. Within a temperature gradient applied to such compounds over a longer period of time, a mass transport can occur leading to a certain ion gradient in the samples . As a consequence, a degradation of the material might occur due to this defined mass transport and a possible phase separation tendency.…”

Section: Introductionmentioning

confidence: 99%

Phase Segregation of Polymorphic Solid Ion Conducting Cu₇PSe₆ during Thermoelectric Experiments

Baumer

Nilges

2018

Zeitschrift anorg allge chemie

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Solid ion conductors are moved into the focus of energy‐related science as thermoelectric materials due to their high ion mobility and their ability to scatter phonons. A second interesting phenomenon of some solid ion (and electron) conductors is the possibility to perform a pnp switch of their semiconductor mechanism during a structural phase transition. During our search for new pnp switching systems we examined trimorphic, argyrodite‐type Cu7PSe6 as a potential candidate. Recently, this phase was reported to be a reasonable thermoelectric material, which combines to the statements given above. The ion mobility in a solid can be a beauty or a beast concerning the stability of the compound during thermoelectric operation. In this article we report on the electric conductivity and thermopower evolution of Cu7PSe6, a trimorphic, mixed ion and electron conductor. Slightly above room temperature this compound undergoes an order‐disorder phase transition where Cu tends to become almost liquid in the framework of the anions. Intending to verify the possibility of a pnp switch during this order‐disorder transition we started a systematic evaluation of the (thermo)electrochemical behavior of this phase. Unfortunately, this material does not perform a pnp switch but it also shows a well‐defined decomposition behavior upon thermoelectric cycling. In this contribution we report on the change and evolution of properties during the characterization process, which manifests in a continuous variation of the total electric conductivity and thermopower upon thermoelectric cycling. This study reflects the importance and need of stability studies of solid ion conductors in the entire range of thermoelectric application especially if order‐disorder phase transitions and high ion mobilities are present which can cause significant mass transport and phase separation within the sample.

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Section: Introductionmentioning

confidence: 99%

Phase Segregation of Polymorphic Solid Ion Conducting Cu₇PSe₆ during Thermoelectric Experiments

Baumer

Nilges

2018

Zeitschrift anorg allge chemie

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“…Structural relaxations, recombination of point defects, or formation of grain boundaries with the crystallization of layers might strongly influence the migration of copper. , Furthermore, the pinholes inside the ALD layers play an important role in creating pathways for copper migration. The structural defects or surface contamination, in turn, can serve as nucleation sites for pinhole and defect formation. − Additionally, mass diffusion within the ALD layers is another possible mechanism to explain the copper migration. , From the detailed microscopic investigations in this work, we observed that the mode of copper migration depends strongly on the layer stack of Al 2 O 3 /TiO 2 and Al 2 O 3 /SiO 2 .…”

Section: Results and Discussionmentioning

confidence: 76%

“…During annealing, temperature serves as a driving force for the migration of copper within ALD layers, which is directly facilitated by defect structure . Structural relaxations, recombination of point defects, or formation of grain boundaries with the crystallization of layers might strongly influence the migration of copper. , Furthermore, the pinholes inside the ALD layers play an important role in creating pathways for copper migration.…”

Section: Results and Discussionmentioning

confidence: 99%

In Situ X-ray Diffraction and Spectro-Microscopic Study of ALD Protected Copper Films

Dogan

Sanli

Hahn

et al. 2020

ACS Appl. Mater. Interfaces

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In many applications of copper in industry and research, copper migration and degradation of metallic copper to its oxides is a common problem. There are numerous ways to overcome this degradation with varying success. Atomic layer deposition (ALD) based encapsulation and passivation of the metallic copper recently emerged as a serious route to success owing to the conformality and density of the ALD films. So far, the majority of the studies have been focused on corrosion protection of copper in a variety of chemical environments, mostly at ambient temperature. An investigation of the stability of the ALD film stacks and copper’s interaction with them at elevated temperatures has been lacking. Here, we study the mitigation of copper oxidation and migration in 50 nm thick Al2O3/TiO2 and Al2O3/SiO2 bilayer ALD stacks. First, the corrosion dynamics were investigated via in situ X-ray diffraction (XRD) at 350 °C under atmospheric conditions, and second, the interaction of copper with the passivation layers have been examined post factum using detailed spectro-microscopic investigations. According to the XRD results, both ALD films exhibited excellent oxidation protection. In contrast, bare Cu immediately started to oxidize at 350 °C and transformed entirely to its known oxide phases in 4 h. Spectro-microscopic studies revealed that there are structural and chemical changes on the top surface and within the film stacks. The TiO2 layer was crystallized during annealing, while the SiO2 layer stayed in the amorphous phase, which was analyzed by grazing incidence XRD and transmission electron microscopy. According to scanning electron microscopy and X-ray photoelectron spectroscopy analysis, copper was detected on the surface with a higher amount in Al2O3/TiO2 than Al2O3/SiO2, 5.2 at.% and 0.7 at.%, respectively. Based on the surface and cross-sectional analysis, copper migration was observed on both layers, albeit more substantially in Al2O3/TiO2. In the case of Al2O3/SiO2, the bulk of the copper was captured at the interface of the two oxides.

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“…$$ For Sr 2+ diffusion in bovine bone marrow, we assumed diffusion from an exhaustless source into semi‐infinite space as boundary conditions for solving Fick's second law of diffusion (Equation []), as previously described 26,27,53,54 . Following assumptions had to be made 55 : Because species concentration c is proportional to secondary ion intensity I in SIMS, the fit can be carried out with the obtained Sr + ion signal intensities. The measured ion intensity I is considered as a linear function of the real Sr 2+ intensity ( I bg ). Strontium diffusion occurs from an infinite reservoir of Sr 2+ with an intensity I 0 at the initial position x 0 . There are no reactions of Sr 2+ (diffusing species) with the bone marrow matrix. …”

Section: Resultsmentioning

confidence: 99%

Determination of Sr²⁺ mobility in viscous bovine bone marrow by cryo‐time‐of‐flight secondary ion mass spectrometry

Kern

Pauli

Rohnke

2022

Rapid Comm Mass Spectrometry

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In osteoporosis research, strontium ions (Sr 2+ ) have emerged as promising therapeutic agent in modified bone cements for better fracture healing. Modeling of Sr 2+ dispersion in bone could be used as a predictive tool for the evaluation of functionalized biomaterials in future. Therefore, determination of experimental parameters for Sr 2+ transport in bone is essential. In this study, we focus on the determination of Sr 2+ diffusion in viscous bovine bone marrow by time-of-flight secondary ion mass spectrometry (ToF-SIMS).Methods: For this comparatively fast diffusion (FD) experiment, a specific experimental protocol of ToF-SIMS depth profiling under cryogenic conditions was developed. The validity of our experimental approach is proven by a timedependent experimental series. Furthermore, 2D and 3D mass spectrometric imaging analysis was used to study Sr 2+ surface and bulk distribution within bovine bone marrow.Results: Detailed 2D and 3D mass spectrometric imaging analysis revealed that Sr 2+ diffusion is slower in bone marrow areas with high intensity of lipid and fatty acid signals than in areas with less lipid content. The Sr 2+ transport within this passive model can be described by Fickian diffusion. Average diffusion coefficients of Sr 2+ in bovine bone marrow were obtained from diffusion profiles in FD areas (D bovine,FD = [2.09 ± 2.39]Á10 À9 cm 2 s À1 ), slow diffusion areas (D bovine,SD = [1.52 ± 1.80]Á10 À10 cm 2 s À1 ), and total area diffusion (D bovine,TA = [1.94 ± 2.40]Á10 À9 cm 2 s À1 ). Conclusions:We were able to show that cryo-ToF-SIMS is a useful tool for the characterization of rapid diffusion in water-containing highly viscous media. To the best of our knowledge, this is the first reported experimental approach for the investigation of the distribution of low concentrated therapeutic agents in bone marrow. Overall, our results provide important insights about Sr 2+ diffusion in bovine bone marrow.

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Chemical diffusion of copper in lead telluride

Cited by 8 publications

References 30 publications

Phase Segregation of Polymorphic Solid Ion Conducting Cu₇PSe₆ during Thermoelectric Experiments

Phase Segregation of Polymorphic Solid Ion Conducting Cu₇PSe₆ during Thermoelectric Experiments

In Situ X-ray Diffraction and Spectro-Microscopic Study of ALD Protected Copper Films

Determination of Sr²⁺ mobility in viscous bovine bone marrow by cryo‐time‐of‐flight secondary ion mass spectrometry

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Chemical diffusion of copper in lead telluride

Cited by 8 publications

References 30 publications

Phase Segregation of Polymorphic Solid Ion Conducting Cu7PSe6 during Thermoelectric Experiments

Phase Segregation of Polymorphic Solid Ion Conducting Cu7PSe6 during Thermoelectric Experiments

In Situ X-ray Diffraction and Spectro-Microscopic Study of ALD Protected Copper Films

Determination of Sr2+ mobility in viscous bovine bone marrow by cryo‐time‐of‐flight secondary ion mass spectrometry

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Phase Segregation of Polymorphic Solid Ion Conducting Cu₇PSe₆ during Thermoelectric Experiments

Phase Segregation of Polymorphic Solid Ion Conducting Cu₇PSe₆ during Thermoelectric Experiments

Determination of Sr²⁺ mobility in viscous bovine bone marrow by cryo‐time‐of‐flight secondary ion mass spectrometry