Research data infrastructure for high-throughput experimental materials science

Numerous phosphorus-rich metal phosphides containing both P–P bonds and metal–P bonds are known from the solid-state chemistry literature. A method to grow these materials in thin-film form would be desirable, as thin films are required in many applications and they are an ideal platform for high-throughput studies. In addition, the high density and smooth surfaces achievable in thin films are a significant advantage for characterization of transport and optical properties. Despite these benefits, there is hardly any published work on even the simplest binary phosphorus-rich phosphide films. Here, we demonstrate growth of single-phase CuP2 films by a two-step process involving reactive sputtering of amorphous CuP2+x and rapid annealing in an inert atmosphere. At the crystallization temperature, CuP2 is thermodynamically unstable with respect to Cu3P and P4. However, CuP2 can be stabilized if the amorphous precursors are mixed on the atomic scale and are sufficiently close to the desired composition (neither too P poor nor too P rich). Fast formation of polycrystalline CuP2, combined with a short annealing time, makes it possible to bypass the diffusion processes responsible for decomposition. We find that thin-film CuP2 is a 1.5 eV band gap semiconductor with interesting properties, such as a high optical absorption coefficient (above 105 cm–1), low thermal conductivity (1.1 W/(K m)), and composition-insensitive electrical conductivity (around 1 S/cm). We anticipate that our processing route can be extended to other phosphorus-rich phosphides that are still awaiting thin-film synthesis and will lead to a more complete understanding of these materials and of their potential applications.

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Section: Methodsmentioning

confidence: 71%

Crystallize It before It Diffuses: Kinetic Stabilization of Thin-Film Phosphorus-Rich Semiconductor CuP₂

et al. 2022

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“…All measurements except for nanocalorimetry and thermoelectric/Hall effect characterization were performed within 24 h after annealing to avoid sample degradation. The combinatorial characterization data arising from compositional gradients in the films was managed with the COMBIgor tool, 43 the Research Data Infrastructure, 44 and integrated into the High-Throughput Experimental Materials Database. 45 Elemental composition and film thickness were determined by x-ray fluorescence (XRF) calibrated by Rutherford backscattering spectrometry (RBS, composition) and spectroscopic ellipsometry (thickness).…”

Section: B Film Characterizationmentioning

confidence: 99%

Crystallize it before it diffuses: Kinetic stabilization of thin-film phosphorus-rich semiconductor CuP2

Crovetto

Kojda

et al. 2022

Preprint

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Numerous phosphorus-rich metal phosphides containing both P-P bonds and metal-P bonds are known from the solid-state chemistry literature. A method to grow these materials in thin-film form would be desirable, since thin films are required in many applications and they are an ideal platform for high-throughput studies. In addition, the high density and smooth surfaces achievable in thin films are a significant advantage for characterization of transport and optical properties. Despite these benefits, there is hardly any published work on even the simplest binary phosphorus-rich phosphides. Here, we demonstrate growth of single-phase CuP2 films by a two-step process involving reactive sputtering of amorphous CuP{2+x} and rapid annealing in an inert atmosphere. At the temperature required for crystallization, CuP2 tends to decompose into Cu3P and gaseous phosphorus. However, CuP2 can still be synthesized if the amorphous precursors are mixed on the atomic scale and are sufficiently close to the desired composition (neither too P poor nor too P rich). Fast formation of polycrystalline CuP2, combined with a short annealing time, makes it possible to bypass the diffusion processes responsible for decomposition. We find that thin-film CuP2 is a 1.5 eV band gap semiconductor with interesting properties, such as a high optical absorption coefficient (above 1e5 cm-1), low thermal conductivity (1.1 W/Km), and composition-insensitive electrical conductivity (around 1 S/cm). We anticipate that our processing route can be extended to other phosphorus-rich phosphides that are still awaiting thin-film synthesis, and will lead to more complete understanding of these materials and of their potential applications.

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“…Experimental combinatorial data for this study have been analyzed using the COMBIgor software package 48 and are publicly available in the National Renewable Energy Laboratory (NREL) high-throughput experimental materials database at https://htem.nrel.gov. 49,50 Cation composition was measured with electron probe microanalysis (EPMA) measuring the Al Kα, N Kα, O Kα, Si Kα, and Gd M α X-ray signals. Extra steps were taken for quantitative analysis of light elements: the sample was fluoresced at different depths using several beam energies (5, 10, and 15 keV), and k-ratios were determined at each.…”

Section: Thin Film Growth and Characterizationmentioning

confidence: 99%

Synthesis and Calculations of Wurtzite Al1−xGdxN Heterostructural Alloys

Smaha

Yazawa

Norman

et al. 2022

Preprint

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Al1−xGdxN is one of a series of novel heterostructural alloys involving rare earth cations with potentially interesting properties for (opto)electronic, magnetic and neutron detector applications. Using alloy models in conjunction with density functional theory, we explored the full composition range for Al1−xGdxN and found that wurtzite is the ground state structure up to a critical composition of x = 0.82. The calculated temperature-composition phase diagram reveals a large miscibility gap inducing spinodal decomposition at equilibrium conditions, with higher Gd substitution (meta)stabilized at higher temperatures. By depositing combinatorial thin films at high effective temperatures using radio frequency co-sputtering, we have achieved the highest Gd3+ incorporation into the wurtzite phase reported to date, with single-phase compositions at least up to x ≈ 0.25 confirmed by high resolution synchrotron grazing incidence wide angle X-ray scattering. High resolution transmission electron microscopy on material with x ≈ 0.13 confirmed a uniform composition polycrystalline film with uniform columnar grains having the wurtzite structure. Expanding our calculations to other rare earth cations (Pr and Tb) reveals similar thermodynamic stability and solubility behavior to Gd. From this and previous studies on Al1−xScxN, we elucidate that both smaller ionic radius and higher bond ionicity promote increased incorporation of group IIIB cations into wurtzite AlN. This work furthers the development of design rules for new alloys in this materials family.

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Research data infrastructure for high-throughput experimental materials science

Cited by 27 publications

References 30 publications

Crystallize It before It Diffuses: Kinetic Stabilization of Thin-Film Phosphorus-Rich Semiconductor CuP₂

Crystallize It before It Diffuses: Kinetic Stabilization of Thin-Film Phosphorus-Rich Semiconductor CuP₂

Crystallize it before it diffuses: Kinetic stabilization of thin-film phosphorus-rich semiconductor CuP2

Synthesis and Calculations of Wurtzite Al1−xGdxN Heterostructural Alloys

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Research data infrastructure for high-throughput experimental materials science

Cited by 27 publications

References 30 publications

Crystallize It before It Diffuses: Kinetic Stabilization of Thin-Film Phosphorus-Rich Semiconductor CuP2

Crystallize It before It Diffuses: Kinetic Stabilization of Thin-Film Phosphorus-Rich Semiconductor CuP2

Crystallize it before it diffuses: Kinetic stabilization of thin-film phosphorus-rich semiconductor CuP2

Synthesis and Calculations of Wurtzite Al1−xGdxN Heterostructural Alloys

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Product

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Crystallize It before It Diffuses: Kinetic Stabilization of Thin-Film Phosphorus-Rich Semiconductor CuP₂

Crystallize It before It Diffuses: Kinetic Stabilization of Thin-Film Phosphorus-Rich Semiconductor CuP₂