Correlation between optical properties surface morphology of porous silicon electrodeposited by Fe 3+ ion

Abstract

In this paper, we analyze the photoluminescence spectra (PL) of porous silicon (PS) layer which is elaborated by electrochemical etching and passivated by Fe 3+ 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.

Effect of deposition time on the optical properties of vanadium pentoxide films grown on porous silicon nanostructure

“…The surface morphology of V 2 O 5 contains irregular nano akes interconnected to each other with the appearance of cracks and ssures on the outer surfaces with different lengths and orientations. A similar morphology containing cracks has been observed for layers of metal oxides such as iron oxide deposited on a PS matrix [22]. The presence of pores under the deposited layer promotes the formation of cracks across its surface leaving distinctive nano akes.…”

Temperature dependent optical properties of ZnO thin film using ellipsometry and photoluminescence

“…Varshni [41], Cody [42], Vina [43]… However, no physical origin of the modification of E FX transition is clearly given by these models. Indeed here, this recorded shift can be explained by the contribution of two phenomena: the lattice expansion and the electron-phonon interactions [44].…”

Optical Study of Porous Silicon Layers Produced Electrochemically for Photovoltaic Application

“…ii. While increasing the intensity of PL in the temperature range of (50 K ≤ T ≤ 80 K) indicates that the excitons are trapped in the lower localized states are thermally activated toward the higher states and then recombine radiatively and generate an increase in IPL intensity [32].…”

“…iii. At higher temperatures (T ≥ 80 K), thermal activation becomes more dominant and localized excitons become free and can diffuse in a non-radiative manner in the structure leading to a decrease in the intensity of PL [32].…”