Correlation between optical properties surface morphology of porous silicon electrodeposited by Fe3+ ion

Asma Mabrouk (1) , Nathalie Lorrain (2) , Lazhar Mohamed Haji (2) , Maherzi Oueslati (1)

1 Laboratoire de Spectroscopie Raman
2 FOTON - Fonctions Optiques pour les Technologies de l'informatiON

In this paper, we analyze the photoluminescence spectra (PL) of porous silicon (PS) layer which is elaborated by electrochemical etching and passivated by Fe3+ ions (PSF) via current density, electro-deposition and temperature measurements. We observe unusual surface morphology of PSF surface and anomalous emission behavior. The PSF surface shows regular distribution of cracks, leaving isolated regions or "platelets" of nearly uniform thickness. These cracks become more pronounced for high current densities. The temperature dependence of the PL peak energy (E PL) presents anomalous behaviors ,i.e., the PL peak energy shows a successive red/blue/redshift (S-shaped behavior) with increasing temperature that we attribute to the existence of strong potential fluctuations induced by the electrochemical etching of PS layers. A competition process between localized and delocalized excitons is used to discuss these PL properties. In this case, the potential confinement plays a key role on the enhancement of PL intensity in PSF. To explain the temperature dependence of the PL intensity, we have proposed a recombination model based on the tunneling and dissociation of excitons.

Mots clés: Radiative recombination; Potential fluctuations; Silicon; Nanocristallites

Domaines: Science des matériaux [cond-mat.mtrl-sci]

Asma Mabrouk, Nathalie Lorrain, Lazhar Mohamed Haji, Maherzi Oueslati. Correlation between optical properties surface morphology of porous silicon electrodeposited by Fe3+ ion. Superlattices and Microstructures, 2015, 77, pp.219-231. ⟨10.1016/j.spmi.2014.10.028⟩. ⟨hal-01095824⟩