The New Jersey Institute of Technology's
Electronic Theses & Dissertations Project

Title:	Raman scattering in free standing porous Si films
Author:	Chidambaram, Thenappan
View Online:	njit-etd2008-081 (ix, 36 pages ~ 2.9 MB pdf)
Department:	Department of Electrical and Computer Engineering
Degree:	Master of Science
Program:	Electrical Engineering
Document Type:	Thesis
Advisory Committee:	Tsybeskov, Leonid (Committee chair) Hanafi, Hussein I. (Committee member) Sosnowski, Marek (Committee member)
Date:	2008-05
Keywords:	Porous silicon Raman scattering
Availability:	Unrestricted
Abstract:	In this thesis, Raman Scattering of free standing porous silicon on sapphire samples of controllably varying porosity is studied. The free standing, fully crystalline porous silicon films were prepared by electrochemical etching and the porous structure were lifted-off by a procedure based on electro-polishing. During Raman scattering measurements, the samples are exposed to relatively high intensity laser radiation. Free-standing porous Si sample temperature and thermal conductivity are calculated by comparing intensities of Stokes and anti-Stokes Raman peaks. Compared to crystalline Si, we find strong decrease in thermal conductivity accompanied by a change in the phonon spectra. Also, comparing Stokes and anti-Stokes Raman spectra, we find that porous Si is a nano-composite material with a complex morphology and variety of crystallites sizes. The porous silicon layers can be used for thermal isolation and as floating substrates for lattice-mismatched hetero-integration.