Optical polarization anisotropy in strained A-plane GaN films on R-plane sapphire

Ghosh, Sandip
Misra, Pranob
Grahn, Holger T.
İmer, Muhsine Bilge
Nakamura, Shuji
DenBaars, Steven P.
Speck, James S.
We have used polarized photoreflectance (PR) spectroscopy to study [1120]-oriented A-plane GaN films on R-plane sapphire substrates. For this type of films, the c-axis of GaN lies in the film plane. When the probe beam is polarized perpendicular to the c-axis, we observe a single feature in the PR spectrum, while two features at higher energies are observed for parallel polarization. Comparing the transition energies with the ones obtained by electronic band-structure calculations, we identify the observed PR spectral features as the three possible transitions around the fundamental band gap of GaN. However in comparison to unstrained GaN, their polarization properties and energies have been significantly modified by the inplane anisotropic strain in the film. Finally, we can also determine the individual in-plane anisotropic strain components.


Hasanlı, Nızamı; MELNIK, NN; RAGIMOV, AS (Wiley, 1983-01-01)
Measurements are made of polarized Raman scattering and infrared reflection spectra of twenty two compositions of GaS1‐xSex layer mixed crystals grown by the Bridgman method. Besides the usual one‐mode and two‐mode behaviours of phonon modes, a number of more complex dependences characterized by the appearance of additional bands in the spectra of mixed crystals are observed. Their appearance is accounted for by the uncovering of the Brillouin zone due to the disturbance of the periodicity of the crystal la...
Optical constants of Tl4Ga3InSe8 layered single crystals
Goksen, K.; Hasanlı, Nızamı (Elsevier BV, 2007-11-15)
The optical properties of Tl(4)Ga(3)lnSe(8) layered single crystals have been studied by means of transmission and reflection measurements in the wavelength range of 500-1100 run. The analysis of the room temperature absorption data revealed the presence of both optical indirect and direct transitions with band gap energies of 1.94 and 2.20 eV, respectively. Transmission measurements carried out in the temperature range of 10-300 K revealed that the rate of change of the indirect band gap with temperature i...
Optical constants of silver and copper indium ternary sulfides from infrared reflectivity measurements
Hasanlı, Nızamı (Elsevier BV, 2016-03-01)
Infrared reflection spectra are obtained in the frequency range of 50-2000 cm(-1) for AgIn5S8 and CuIn5S8 single crystals grown by Bridgman method. All four infrared-active modes are detected, which are in full agreement with the prediction of group-theoretical analysis. Spectral dependence of optical parameters; real and imaginary parts of the dielectric function, the function of energy losses, refractive index, absorption index and absorption coefficient were calculated from reflectivity experiments. The ...
Multiphonon absorption processes in layered structured TlGaS2, TlInS2 and TlGaSe2 single crystals
IŞIK, MEHMET; Hasanlı, Nızamı; KORKMAZ ÖZKAN, FİLİZ (Elsevier BV, 2013-07-15)
The infrared transmittance and Raman scattering spectra in TlGaS2, TlInS2 and TlGaSe2 layered single crystals grown by Bridgman method were studied in the frequency ranges of 400-1500 and 10-400 cm(-1), respectively. Three, three and five bands observed at room temperature in IR transmittance spectra of TlGaS2, TlInS2 and TlGaSe2, respectively, were interpreted in terms of multiphonon absorption processes. (C) 2013 Elsevier By. All rights reserved.
Polarization anisotropy in nonpolar oriented GaN films studied by polarized photoreflectance spectroscopy
Behn, Udo; Misra, Pranob; Grahn, Holger T.; İmer, Muhsine Bilge; Nakamura, Shuji; DenBaars, Steven P.; Speck, James S. (Wiley, 2007-01-01)
We have used polarized photoreflectance spectroscopy to study the electronic-band-structure modification of GaN films grown along different nonpolar orientations due to biaxial, anisotropic in-plane strain. For nonpolar oriented films, the c-axis of GaN lies in the film plane. An unstrained, high-quality C-plane GaN film is used to estimate the difference in the band gap energies between 10 K and room temperature. We use the crystal-field and spin-orbit splitting energies and the deformation potential D, de...
Citation Formats
S. Ghosh et al., “Optical polarization anisotropy in strained A-plane GaN films on R-plane sapphire,” PHYSICA STATUS SOLIDI B-BASIC SOLID STATE PHYSICS, pp. 1441–1445, 2006, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/48139.