Infrared reflectance of optical phonon modes in AlGaN epitaxial layers grown on sapphire substrates

Jun Rong Chen, Tien Chang Lu, Gen Sheng Huang, Tsung-Shine Ko, Hao Chung Kuo, Shing Chung Wang

Research output: Chapter in Book/Report/Conference proceedingConference contribution

4 Citations (Scopus)

Abstract

We reported the systematical study of optical properties of hexagonal Al x Ga 1-x N epitaxial films grown on c-sapphire substrate using metal-organic chemical vapor deposition. By performing Fourier transform infrared spectroscopy measurements, the high-frequency dielectric constants and phonon frequencies can be obtained by theoretically fitting the experimental infrared reflectance spectra using a four-phase layered model. The high-frequency dielectric constant of Al x Ga 1-x N varies between 4.98 and 4.52 for ε ∞⊥ (polarization perpendicular to the optical axis) and between 4.95 and 4.50 for ε ∞,// (polarization parallel to the optical axis) respectively when the aluminum composition changes from 0.15 to 0.24. Furthermore, from experimental infrared reflectance spectra of Al x Ga 1-x N films, a specific absorption dip at 785 cm -1 was observed when the aluminum composition is larger than 0.24. The dip intensity increases and the dip frequency shifts from 785 to 812 cm -1 as aluminum composition increases from 0.24 to 0.58. According to the reciprocal space map of x-ray diffraction measurements, the emergence of this dip could be resulted from the effects of strain relaxation in AlGaN epitaxial layers due to the large lattice mismatch between GaN and AlGaN epitaxial film.

Original languageEnglish
Title of host publicationGallium Nitride Materials and Devices III
DOIs
Publication statusPublished - 2008 Apr 21
EventSociety of Photo-Optical Instrumentation Engineers (SPIE) - San Jose, CA, United States
Duration: 2008 Jan 212008 Jan 24

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
Volume6894
ISSN (Print)0277-786X

Other

OtherSociety of Photo-Optical Instrumentation Engineers (SPIE)
CountryUnited States
CitySan Jose, CA
Period08-01-2108-01-24

Fingerprint

AlGaN
Aluminum Oxide
Sapphire
Epitaxial layers
Phonon
Aluminum
Reflectance
sapphire
Infrared
Epitaxial films
Dielectric Constant
Substrate
Infrared radiation
aluminum
reflectance
Permittivity
Polarization
Substrates
Chemical analysis
permittivity

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering

Cite this

Chen, J. R., Lu, T. C., Huang, G. S., Ko, T-S., Kuo, H. C., & Wang, S. C. (2008). Infrared reflectance of optical phonon modes in AlGaN epitaxial layers grown on sapphire substrates. In Gallium Nitride Materials and Devices III [68941U] (Proceedings of SPIE - The International Society for Optical Engineering; Vol. 6894). https://doi.org/10.1117/12.760296
Chen, Jun Rong ; Lu, Tien Chang ; Huang, Gen Sheng ; Ko, Tsung-Shine ; Kuo, Hao Chung ; Wang, Shing Chung. / Infrared reflectance of optical phonon modes in AlGaN epitaxial layers grown on sapphire substrates. Gallium Nitride Materials and Devices III. 2008. (Proceedings of SPIE - The International Society for Optical Engineering).
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title = "Infrared reflectance of optical phonon modes in AlGaN epitaxial layers grown on sapphire substrates",
abstract = "We reported the systematical study of optical properties of hexagonal Al x Ga 1-x N epitaxial films grown on c-sapphire substrate using metal-organic chemical vapor deposition. By performing Fourier transform infrared spectroscopy measurements, the high-frequency dielectric constants and phonon frequencies can be obtained by theoretically fitting the experimental infrared reflectance spectra using a four-phase layered model. The high-frequency dielectric constant of Al x Ga 1-x N varies between 4.98 and 4.52 for ε ∞⊥ (polarization perpendicular to the optical axis) and between 4.95 and 4.50 for ε ∞,// (polarization parallel to the optical axis) respectively when the aluminum composition changes from 0.15 to 0.24. Furthermore, from experimental infrared reflectance spectra of Al x Ga 1-x N films, a specific absorption dip at 785 cm -1 was observed when the aluminum composition is larger than 0.24. The dip intensity increases and the dip frequency shifts from 785 to 812 cm -1 as aluminum composition increases from 0.24 to 0.58. According to the reciprocal space map of x-ray diffraction measurements, the emergence of this dip could be resulted from the effects of strain relaxation in AlGaN epitaxial layers due to the large lattice mismatch between GaN and AlGaN epitaxial film.",
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Chen, JR, Lu, TC, Huang, GS, Ko, T-S, Kuo, HC & Wang, SC 2008, Infrared reflectance of optical phonon modes in AlGaN epitaxial layers grown on sapphire substrates. in Gallium Nitride Materials and Devices III., 68941U, Proceedings of SPIE - The International Society for Optical Engineering, vol. 6894, Society of Photo-Optical Instrumentation Engineers (SPIE), San Jose, CA, United States, 08-01-21. https://doi.org/10.1117/12.760296

Infrared reflectance of optical phonon modes in AlGaN epitaxial layers grown on sapphire substrates. / Chen, Jun Rong; Lu, Tien Chang; Huang, Gen Sheng; Ko, Tsung-Shine; Kuo, Hao Chung; Wang, Shing Chung.

Gallium Nitride Materials and Devices III. 2008. 68941U (Proceedings of SPIE - The International Society for Optical Engineering; Vol. 6894).

Research output: Chapter in Book/Report/Conference proceedingConference contribution

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AU - Chen, Jun Rong

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AU - Huang, Gen Sheng

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AU - Kuo, Hao Chung

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N2 - We reported the systematical study of optical properties of hexagonal Al x Ga 1-x N epitaxial films grown on c-sapphire substrate using metal-organic chemical vapor deposition. By performing Fourier transform infrared spectroscopy measurements, the high-frequency dielectric constants and phonon frequencies can be obtained by theoretically fitting the experimental infrared reflectance spectra using a four-phase layered model. The high-frequency dielectric constant of Al x Ga 1-x N varies between 4.98 and 4.52 for ε ∞⊥ (polarization perpendicular to the optical axis) and between 4.95 and 4.50 for ε ∞,// (polarization parallel to the optical axis) respectively when the aluminum composition changes from 0.15 to 0.24. Furthermore, from experimental infrared reflectance spectra of Al x Ga 1-x N films, a specific absorption dip at 785 cm -1 was observed when the aluminum composition is larger than 0.24. The dip intensity increases and the dip frequency shifts from 785 to 812 cm -1 as aluminum composition increases from 0.24 to 0.58. According to the reciprocal space map of x-ray diffraction measurements, the emergence of this dip could be resulted from the effects of strain relaxation in AlGaN epitaxial layers due to the large lattice mismatch between GaN and AlGaN epitaxial film.

AB - We reported the systematical study of optical properties of hexagonal Al x Ga 1-x N epitaxial films grown on c-sapphire substrate using metal-organic chemical vapor deposition. By performing Fourier transform infrared spectroscopy measurements, the high-frequency dielectric constants and phonon frequencies can be obtained by theoretically fitting the experimental infrared reflectance spectra using a four-phase layered model. The high-frequency dielectric constant of Al x Ga 1-x N varies between 4.98 and 4.52 for ε ∞⊥ (polarization perpendicular to the optical axis) and between 4.95 and 4.50 for ε ∞,// (polarization parallel to the optical axis) respectively when the aluminum composition changes from 0.15 to 0.24. Furthermore, from experimental infrared reflectance spectra of Al x Ga 1-x N films, a specific absorption dip at 785 cm -1 was observed when the aluminum composition is larger than 0.24. The dip intensity increases and the dip frequency shifts from 785 to 812 cm -1 as aluminum composition increases from 0.24 to 0.58. According to the reciprocal space map of x-ray diffraction measurements, the emergence of this dip could be resulted from the effects of strain relaxation in AlGaN epitaxial layers due to the large lattice mismatch between GaN and AlGaN epitaxial film.

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BT - Gallium Nitride Materials and Devices III

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Chen JR, Lu TC, Huang GS, Ko T-S, Kuo HC, Wang SC. Infrared reflectance of optical phonon modes in AlGaN epitaxial layers grown on sapphire substrates. In Gallium Nitride Materials and Devices III. 2008. 68941U. (Proceedings of SPIE - The International Society for Optical Engineering). https://doi.org/10.1117/12.760296