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Eur. Phys. J. Appl. Phys. 42, 99-102 (2008)
DOI: 10.1051/epjap:2008042
Strain effects of InP/Si and InP/porous Si studied by spectroscopic ellipsometry
M. Lajnef1, N. Ben Sedrine1, J.C. Harmand2, L. Travers2, H. Ezzaouia1 and R. Chtourou11 Laboratoire de Photovoltaïque et de Semiconducteurs, Centre de Recherche des Sciences et Technologies de l'Énergie, BP 95, Hammam-Lif 2050, Tunisia
2 Laboratoire de Photonique et de Nanostructures, CNRS, Route de Nozay, 91460 Marcoussis, France
Mohamed.lajnef@yahoo.fr
(Received: 3 August 2007 / Received in final form: 13 January 2008 / Accepted: 5 February 2008 / Published online: 28 March 2008)
Abstract
In this work, we study the optical interband transitions of InP on silicon
(InP/Si) and on porous silicon (InP/PSi) substrates grown by molecular beam
epitaxy (MBE). Spectroscopic ellipsometry for photon energies from 2 to 5 eV
is used to determine the InP/Si and InP/PSi complex refractive index and
thickness. Bruggeman effective medium approximation (EMA) associated to the
Cauchy model are used to model the experimental ellipsometric data. We have
found that the E1 and E1 +
transition energies
of InP/Si and InP/PSi shift to low energies compared to bulk InP. This
effect is interpreted as a result of the strain relaxation of the InP layers
grown respectively on Si and porous Si substrates.
78.55.Cr - III-V semiconductors.
95.55.Qf - Photometric, polarimetric, and spectroscopic instrumentation.
68.35.Gy - Mechanical properties; surface strains.
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