An infrared dielectric function model for amorphous solids

1992 ◽  
Vol 71 (1) ◽  
pp. 1-6 ◽  
Author(s):  
R. Brendel ◽  
D. Bormann
1999 ◽  
Vol 595 ◽  
Author(s):  
J. Wagner ◽  
A. Ramakrishnan ◽  
H. Obloh ◽  
M. Kunzer ◽  
K. Köhler ◽  
...  

AbstractSpectroscopic ellipsometry (SE) has been used for the characterization of AlGaN/GaN and InGaN/GaN heterostructures. The resulting pseudodielectric function spectra were analyzed using a multilayer approach, describing the dielectric functions of the individual layers by a parametric oscillator model. From this analysis, the dielectric function spectra of GaN, AlxGa1−xN (x≤0.16), and In0.13Ga0.87N were deduced. Further, the dependence of the AlxGa1−xN band gap energy on the Al mole fraction was derived and compared with photoluminescence data recorded on the same material. The SE band gap data are compatible with a bowing parameter close to 1 eV for the composition dependence of the AlxGa1−xN gap energy. Finally, the parametric dielectric functions have been used to model the pseudodielectric function spectrum of a complete GaN/AlGaN/InGaN LED structure.


Author(s):  
S. Basu ◽  
B. J. Lee ◽  
Z. M. Zhang

This paper describes a theoretical investigation of near-field radiative heat transfer between doped silicon surfaces separated by a vacuum gap. Using an improved dielectric function model for heavily doped silicon, along with fluctuation-dissipation theorem, and dyadic Green’s function, the present authors calculated the energy transfer between the doped silicon surfaces near room temperature. The effects of doping level, polarization, and width of the vacuum gap on the overall radiative transfer were investigated. It was observed that increase in the doping concentration of the emitter does not necessarily enhance the energy transfer in the near field. The energy-streamline method was used to model the lateral shift of the energy pathway, which is the trace of the Poynting vectors in the vacuum gap. The analysis performed in this study may facilitate the understanding of near-field radiation for applications such as thermal management in nanoelectronics, energy conversion systems, and nanothermal manufacturing.


2007 ◽  
Vol 61 (6) ◽  
pp. 644-648 ◽  
Author(s):  
Domingos De Sousa Meneses ◽  
Benoit Rousseau ◽  
Patrick Echegut ◽  
Guy Matzen

2000 ◽  
Vol 5 (S1) ◽  
pp. 775-781
Author(s):  
J. Wagner ◽  
A. Ramakrishnan ◽  
H. Obloh ◽  
M. Kunzer ◽  
K. Köhler ◽  
...  

Spectroscopic ellipsometry (SE) has been used for the characterization of AlGaN/GaN and InGaN/GaN heterostructures. The resulting pseudodielectric function spectra were analyzed using a multilayer approach, describing the dielectric functions of the individual layers by a parametric oscillator model. From this analysis, the dielectric function spectra of GaN, AlxGa1−xN (x≤0.16), and In0.13Ga0.87N were deduced. Further, the dependence of the AlxGa1−xN band gap energy on the Al mole fraction was derived and compared with photoluminescence data recorded on the same material. The SE band gap data are compatible with a bowing parameter close to 1 eV for the composition dependence of the AlxGa1−xN gap energy. Finally, the parametric dielectric functions have been used to model the pseudodielectric function spectrum of a complete GaN/AlGaN/InGaN LED structure.


2009 ◽  
Vol 132 (2) ◽  
Author(s):  
S. Basu ◽  
B. J. Lee ◽  
Z. M. Zhang

This paper describes a theoretical investigation of near-field radiative heat transfer between doped silicon surfaces separated by a vacuum gap. An improved dielectric function model for heavily doped silicon is employed. The effects of doping level, polarization, and vacuum gap width on the spectral and total radiative transfer are studied based on the fluctuational electrodynamics. It is observed that increasing the doping concentration does not necessarily enhance the energy transfer in the near-field. The energy streamline method is used to model the lateral shift of the energy pathway, which is the trace of the Poynting vectors in the vacuum gap. The local density of states near the emitter is calculated with and without the receiver. The results from this study can help improve the understanding of near-field radiation for applications such as thermophotovoltaic energy conversion, nanoscale thermal imaging, and nanothermal manufacturing.


Author(s):  
Inigo González de Arrieta ◽  
Leire del Campo ◽  
Domingos De Sousa Meneses

The dielectric function of a cerium oxide nanopowder has been investigated by infrared spectroscopy. The use of Bergman’s spectral representation and a semi-quantum dielectric function model allows an accurate retrieval...


2019 ◽  
Vol 33 (7) ◽  
pp. 1007-1019 ◽  
Author(s):  
Ryan A. Mace ◽  
Abigail B. Waters ◽  
Kayle S. Sawyer ◽  
Taylor Turrisi ◽  
David A. Gansler

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