Modeling of Structure, Thermodynamic Properties and Phase Transition Temperaturesof II-VI Crystals

Parashchuk, Taras

doi:10.21272/jnep.8(2).02010

Cited by 3 publications

(2 citation statements)

References 12 publications

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“…First, the material may undergo a phase change. For instance, ZnSe will undergo a phase change at from the zincblende crystal structure to the wurtzite structure at approximately 1400 K [36]. This temperature is easily attained at the focal spot of the ULI process.…”

Section: Physical Processesmentioning

confidence: 99%

Mid-IR Ultrafast Laser Inscribed Waveguides and Devices

McDaniel

Thorburn

Liebig

et al. 2019

2019 IEEE Research and Applications of Photonics in Defense Conference (RAPID)

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MID-IR ULTRAFAST LASER INSCRIBED WAVEGUIDES AND DEVICES Name: McDaniel, Sean A. University of Dayton Advisor: Dr. Gary Cook Ultrafast laser inscription (ULI) is a highly versatile technique for creating index modifications in glasses and crystalline materials. The process of ULI relies on ultrashort laser pulses focused inside of a material. The high intensity of the pulsed beam induces nonlinear absorption processes, which transfers the pulse energy to the material lattice. With careful experimental control of the laser parameters, a permanent change in the refractive can be obtained in the bulk material. The permanent refractive index change obtained by ULI can be used to create waveguides in active laser materials, such as Cr:ZnSe, Fe:ZnSe and Ho:YAG.Transition metal and rare-earth laser sources have been shown to operate over the 2 − 5 µm range. ULI can be used in conjunction with these materials to produce high power, guided-wave structures with reduced size, weight and power (SWaP) requirements. Power levels for Cr:ZnSe and Fe:ZnSe have been scaled to > 5 W and > 1 W respectively in ULI waveguide devices.Additionally, the first Ho:YAG ULI laser has been investigated, exhibiting output powers of ≈ 2 W .In addition to these advances, the theoretical limit for transition metal waveguide lasers was investigated. Transition metal lasers are highly sensitive to the operating temperature of the laser device. If the temperature increase induced in the sample is too high, phonon assisted transitions iii become dominant, thus decreasing the performance of the laser. Laser rate-equations and a thermal model for ULI waveguides were developed to establish a theoretical limit to ULI waveguide operation.Finally, several advancements were made with respect to creating ULI waveguides. An algorithm was developed for creating arbitrary ULI structures from computer generated models. The ability to create arbitrarily generated structures provides the ability to create complex structures using ULI, such as splitters, couplers, and photonic lanterns. Furthermore, a new helical inscription technique was devised for creating smooth index profiles and for creating Bragg structuring. iv ACKNOWLEDGMENTS

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Section: Physical Processesmentioning

confidence: 99%

Mid-IR Ultrafast Laser Inscribed Waveguides and Devices

McDaniel

Thorburn

Liebig

et al. 2019

2019 IEEE Research and Applications of Photonics in Defense Conference (RAPID)

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“…In the diamond-like compounds, only half of the tetrahedral structural voids are filled with cations and all octahedral voids are unoccupied . The binary DLS materials crystallize in the cubic zinc blende (sphalerite) or hexagonal wurtzite structures. , Instead, the ternary and quaternary DLS materials usually have tetragonal structures …”

Section: Introductionmentioning

confidence: 99%

Structure Evolution and Bonding Inhomogeneity toward High Thermoelectric Performance in Cu₂CoSnS_4–xSe_x Materials

et al. 2023

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Lightweight diamond-like structure (DLS) materials are excellent candidates for thermoelectric (TE) applications due to their low costs, eco-friendly nature, and property stability. The main obstacles restricting the energy-conversion performance by the lightweight DLS materials are high lattice thermal conductivity and relatively low carrier mobility. By investigating the anion substitution effect on the structural, microstructural, electronic, and thermal properties of Cu 2 CoSnS 4−x Se x , we show that the simultaneous enhancement of the crystal symmetry and bonding inhomogeneity engineering are effective approaches to enhance the TE performance in lightweight DLS materials. Particularly, the increase of x in Cu 2 CoSnS 4−x Se x makes the DLS structure with the ideal tetrahedral bond angles of 109.5°favorable, leading to better crystal symmetry and higher carrier mobility in samples with higher selenium content. In turn, the phonon transport in the investigated DLS materials is strongly disturbed due to the bonding inhomogeneity between anions and three sorts of cations inducing large lattice anharmonicity. The increase of Se content in Cu 2 CoSnS 4−x Se x only intensified this effect resulting in a lower lattice component of the thermal conductivity (κ L ) for Se-rich samples. As a result of the enhanced power factor S 2 ρ −1 and the low κ L , the dimensionless thermoelectric figure of merit ZT achieves a high value of 0.75 for Cu 2 CoSnSe 4 DLS material. This work demonstrates that crystal symmetry and bonding inhomogeneity play an important role in the transport properties of DLS materials and provide a path for the development of new perspective materials for TE energy conversion.

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CdTe vapor phase condensates on (100) Si and glass for solar cells

Nykyrui

Saliy

Yavorskyi

et al. 2017

2017 IEEE 7th International Conference Nanomaterials: Application &Amp; Properties (NAP)

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Modeling of Structure, Thermodynamic Properties and Phase Transition Temperaturesof II-VI Crystals

Cited by 3 publications

References 12 publications

Mid-IR Ultrafast Laser Inscribed Waveguides and Devices

Mid-IR Ultrafast Laser Inscribed Waveguides and Devices

Structure Evolution and Bonding Inhomogeneity toward High Thermoelectric Performance in Cu₂CoSnS_4–xSe_x Materials

CdTe vapor phase condensates on (100) Si and glass for solar cells

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Modeling of Structure, Thermodynamic Properties and Phase Transition Temperaturesof II-VI Crystals

Cited by 3 publications

References 12 publications

Mid-IR Ultrafast Laser Inscribed Waveguides and Devices

Mid-IR Ultrafast Laser Inscribed Waveguides and Devices

Structure Evolution and Bonding Inhomogeneity toward High Thermoelectric Performance in Cu2CoSnS4–xSex Materials

CdTe vapor phase condensates on (100) Si and glass for solar cells

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Product

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Structure Evolution and Bonding Inhomogeneity toward High Thermoelectric Performance in Cu₂CoSnS_4–xSe_x Materials