Composition dependence of infrared optical phonon modes in AlGaN epilayers grown on sapphire substrates

Author

Chen, Jun-Rong ; Lu, Tien-Chang ; Kuo, Hao-Chung ; Wang, Shing-Chung

Author_Institution

Dept. of Photonics & Inst. of Electro-Opt. Eng., Nat. Chiao Tung Univ., Hsinchu

fYear

2008

fDate

4-9 May 2008

Firstpage

1

Lastpage

2

Abstract

We reported the systematical study of optical anisotropy of Al_xGa_1-xN epitaxial films grown on sapphire using FTIR measurements. The experimental data can be theoretically fitted by employing a four-phase layered model. Several specific absorption dips were observed when the aluminum composition is larger than 24%. The dip intensity increases with the aluminum compositions. According to the reciprocal space map measurements, these dips may be induced due to the effects of strain relaxation in AlGaN epitaxial layers.

Keywords

Fourier transform spectra; III-V semiconductors; aluminium compounds; gallium compounds; infrared spectra; phonons; sapphire; semiconductor epitaxial layers; semiconductor growth; Al₂O₃; AlGaN; AlGaN epilayers; absorption dips; four-phase layered model; infrared optical phonon modes; optical anisotropy; sapphire substrate; strain relaxation; Absorption; Aluminum gallium nitride; Anisotropic magnetoresistance; Epitaxial layers; Geometrical optics; Optical films; Phonons; Semiconductor process modeling; Strain measurement; Substrates;

fLanguage

English

Publisher

iet

Conference_Titel

Lasers and Electro-Optics, 2008 and 2008 Conference on Quantum Electronics and Laser Science. CLEO/QELS 2008. Conference on

Conference_Location

San Jose, CA

Print_ISBN

978-1-55752-859-9

Type

conf

Filename

4572423