Continuous wave photoluminescence emitted by nanostructured porous silicon

Adwan Nayef Hameed Al-Ajili

Department of Physics, College of Science, Al-Imam Mohammed Bin Saud Islamic University, Riyadh, Kingdom of Saudi Arabia.

Email: adwanayef@yahoo.co.

Abstract

The Green to red photoluminescence (PL) emitted by a nanostructured porous silicon (Si) has been investigated by using continuous tuneable UV Synchrotron Radiation Source (SRS) at Daresbury Laboratory in the UK. Three samples have been investigated for green, orange, and red PL emission wavelength, at temperatures 77-295 K. The PL peak is found to shift to shorter wavelengths with decreasing temperature. Information about the nanostructure of porous Si has been determined from PL and Extended X-ray Absorption Fine structure (EXAFS), as well as from electron microscopy. In particular the optical properties of the silicon-based nanostructured materials, obtained from PL have been correlated with structural information from Si K-edge EXAFS. Electron microscopy was used to study the relation between the nanostructure and PL of porous Si, and to investigate porous Si structure. It is found that the samples of different PL spectra have different nanostructures. Platelet Si and Si crystallites in porous Si layers were observed. The size of crystallites ranged from 4 - 10 nm. Diffraction patterns also show these porous Si samples have a crystalline structure.

Keywords

Continuos Wave Photoluminescence, Nanostructure, Porous Silicon, EXAFS, Quantum Confinement.

Corresponding author: Department of Physics, College of Science, Al-Imam Mohammed Bin Saud Islamic University, P.O.Box: 90950, Riyadh 11623, Kingdom of Saudi Arabia.

Fax: +96612581584, Tel: (Office) +96612581947 ,  (Mobile) +966503724679

Email: adwanayef@yahoo.co.uk