Raman and IR reflection spectroscopies of InAsPSb and InPSb
Date Issued
2010
Date
2010
Author(s)
Tzeng, Jian-Shum
Abstract
We investigate lattice vibrational modes of Si-doped InAs, InPSb, and InAsPSb grown by gas-source molecular beam epitaxy(GSMBE) system with Raman spectra and reflectance spectra from FTIR measurement. As far as we know, this is the first investigation about reflectance of InAsPSb quaternary. The Raman spectra of Si-doped InAs epilayers with various carrier concentrations is studied. We observe coupled Plasmon longitudinal phonon (PLP) mode in InAs bulk region and unexpected LO phonon mode within the accumulation layer on InAs surface. Later, We studied Raman spectra of InPSb with different dopant that n type material has higher intensity at InP-like TO position and InAsPSb quaternary which consist of InP-like, InSb-like, and InAs-like LO mode, and these phonon mode shift with various composition. However, InP-like TO mode appearance implies alloy are disordered state, and the samples inside the miscibility gap has higher InP-TO mode intensity.
Finally, we study reflectance spectra of InAsPSb material and apply the theory of complex dielectric equation and boundary conditions about electromagnetic wave in mediums for calculation of reflectivity. We obtain vibration mode information from reflectance spectra. Raman and reflectance spectra of InAsPSb material are in a good agreement about phonon mode. With less As content, InSb-like LO mode is not clearly observed, but it appears in reflectance spectra. Therefore, the two methods are complementary to each other.
Subjects
InAsPSb
LO phonon
TO phonon
Raman
IR reflection spectra
Type
thesis
File(s)![Thumbnail Image]()
Loading...
Name
ntu-99-R97943087-1.pdf
Size
23.32 KB
Format
Adobe PDF
Checksum
(MD5):786bb34a292ae96935e10cab042a4bac