Temperature dependence of the dielectric tensor of monoclinic Ga2O3 single crystals in the spectral range 1.0–8.5 eV

Sturm, Chris; Schmidt‐Grund, Rüdiger; Zviagin, Vitaly; Grundmann, Marius

doi:10.1063/1.4999763

Cited by 21 publications

(21 citation statements)

References 21 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Specifically, the optical properties of monoclinic β-Ga 2 O 3 were investigated in detail. Because of low crystal symmetry, phonon contributions [10,11] and interband transitions [11][12][13] are described by dielectric tensors containing four different nonzero tensor components. The Raman selection rules and tensor components are strongly influenced by the anisotropic properties of the material [14,15].…”

Section: Introductionmentioning

confidence: 99%

Ordinary dielectric function of corundumlike α−Ga2O3 from 40 meV to 20 eV

Feneberg

Nixdorf

Neumann

et al. 2018

Phys. Rev. Materials

View full text Add to dashboard Cite

The linear optical response of metastable α-Ga 2 O 3 is investigated by spectroscopic ellipsometry. We determine the ordinary dielectric function from lattice vibrations up to the vacuum ultraviolet spectral range at room temperature for a sample with a (0001) surface. Three out of four E u infrared-active phonon modes are unambiguously determined, and their frequencies are in good agreement with density functional theory calculations. The dispersion of the refractive index in the visible and ultraviolet part of the spectrum is determined. High-energy interband transitions are characterized up to 20 eV. By comparison with the optical response of α-Al 2 O 3 and with theoretical results, a tentative assignment of interband transitions is proposed.

show abstract

Section: Introductionmentioning

confidence: 99%

Ordinary dielectric function of corundumlike α−Ga2O3 from 40 meV to 20 eV

Feneberg

Nixdorf

Neumann

et al. 2018

Phys. Rev. Materials

View full text Add to dashboard Cite

show abstract

“…Generalized spectroscopic ellipsometry permits measurements of the optical properties of arbitrarily anisotropic materials, 36,72,73 including crystalline materials with monoclinic 37,[41][42][43][44]47,60,61,74 and triclinic symmetry. 75 The Mueller matrix is measured, and then compared with model calculations.…”

Section: Generalized Ellipsometrymentioning

confidence: 99%

“…36 For example, monoclinic β-Ga 2 O 3 , which has gained attention for high power solid state transistor and switch applications, has been analyzed from the terahertz to the vacuum ultra violet spectral regions for its complete phonon mode and free charge carrier properties, [37][38][39][40] and electronic band-to-band transitions as well as its static and highfrequency dielectric constants, indices of refraction, and extinction coefficients. [41][42][43][44][45] A similar analysis procedure resulted in complete sets of phonon modes for monoclinic scintillator material cadmium tungstate (CdWO 4 ) 46 and YSO. 47 To date, the only generalized spectroscopic ellipsometry investigation of LSO was reported by Jellison et al, and the four real-valued dielectric function tensor spectra were obtained in the spectral range from 200 nm to 850 nm.…”

Section: Introductionmentioning

confidence: 99%

Infrared active phonons in monoclinic lutetium oxyorthosilicate

Stokey

Mock

Korlacki

et al. 2020

Journal of Applied Physics

View full text Add to dashboard Cite

A combined generalized spectroscopic ellipsometry measurement and density functional theory calculation analysis is performed to obtain the complete set of infrared active phonon modes in Lu2SiO5 with monoclinic crystal structure. Two different crystals, each cut perpendicular to a different crystal axis are investigated. Ellipsometry measurements from 40 -1200 cm −1 are used to determine the frequency dependent dielectric function tensor elements. The eigendielectric displacement vector summation approach and eigendielectric displacement loss vector summation approach both augmented with anharmonic lattice broadening parameters proposed recently for low-symmetry crystal structures [A. Mock et al., Phys. Rev. B 95, 165202 (2017)] are applied for our ellipsometry data analysis. All measured and model calculated dielectric function tensor and inverse dielectric function tensor elements match excellently. 23 Au symmetry and 22 Bu symmetry infrared active transverse and longitudinal optical modes are found. We also determine the directional limiting modes and the order of the phonon modes within the monoclinic plane. Results from density functional theory and ellipsometry measurements are compared and nearly perfect agreement is observed. We further compare our results to those obtained recently for the monoclinic crystal Y2SiO5, which is isostructural to Lu2SiO5 [A. Mock et al., Phys. Rev. B 97, 165203 (2018)]. We find that the lattice mode behavior of monoclinic Lu2SiO5 is qualitatively identical with Y2SiO5, and differs only quantitatively. We anticipate that members of the isostructural group of monoclinic symmetry oxyorthosilicates such as Dy2SiO5 or Yb2SiO5 will likely behave very similar in their phonon mode properties as reported here for Lu2SiO5.

show abstract

“…A full study of n (λ, T ) in this oxide still needs to be further discussed. Indeed, even though it is of great importance for the application of this very relevant material in photonics, just a few studies have been reported [ 9 , 10 , 11 , 12 ]. The work by Bhaumik et al [ 10 ] used the prism method to obtain the refractive index at temperatures between room temperature (RT, 25 °C, i.e., 298 K) and 200 °C (473 K).…”

Section: Introductionmentioning

confidence: 99%

Temperature-Dependent Anisotropic Refractive Index in β-Ga2O3: Application in Interferometric Thermometers

et al. 2023

View full text Add to dashboard Cite

An accurate knowledge of the optical properties of β-Ga2O3 is key to developing the full potential of this oxide for photonics applications. In particular, the dependence of these properties on temperature is still being studied. Optical micro- and nanocavities are promising for a wide range of applications. They can be created within microwires and nanowires via distributed Bragg reflectors (DBR), i.e., periodic patterns of the refractive index in dielectric materials, acting as tunable mirrors. In this work, the effect of temperature on the anisotropic refractive index of β-Ga2O3 n(λ,T) was analyzed with ellipsometry in a bulk crystal, and temperature-dependent dispersion relations were obtained, with them being fitted to Sellmeier formalism in the visible range. Micro-photoluminescence (μ-PL) spectroscopy of microcavities that developed within Cr-doped β-Ga2O3 nanowires shows the characteristic thermal shift of red–infrared Fabry–Perot optical resonances when excited with different laser powers. The origin of this shift is mainly related to the variation in the temperature of the refractive index. A comparison of these two experimental results was performed by finite-difference time-domain (FDTD) simulations, considering the exact morphology of the wires and the temperature-dependent, anisotropic refractive index. The shifts caused by temperature variations observed by μ-PL are similar, though slightly larger than those obtained with FDTD when implementing the n(λ,T) obtained with ellipsometry. The thermo-optic coefficient was calculated.

show abstract

Temperature dependence of the dielectric tensor of monoclinic Ga2O3 single crystals in the spectral range 1.0–8.5 eV

Cited by 21 publications

References 21 publications

Ordinary dielectric function of corundumlike α−Ga2O3 from 40 meV to 20 eV

Ordinary dielectric function of corundumlike α−Ga2O3 from 40 meV to 20 eV

Infrared active phonons in monoclinic lutetium oxyorthosilicate

Temperature-Dependent Anisotropic Refractive Index in β-Ga2O3: Application in Interferometric Thermometers

Contact Info

Product

Resources

About