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Troudi M.,Lyon Institute of Nanotechnologies | Troudi M.,University of Monastir | Sghaier N.,University of Monastir | Sghaier N.,Institute Preparatoire Aux Etudes Dingenieurs Of Nabeul Ipein | And 2 more authors.
IOP Conference Series: Materials Science and Engineering | Year: 2010

In this paper we present analysis of charge fluctuation in QD (Si-nanocrystals) situated inside the oxide of small area single electron photo-detector (photo-SET or nanopixel). The relationship between excitation signal (photons) and random-telegraph-signal (RTS) was evidenced. We have demonstrated that photoinduced RTS (complex RTS signal) observed on a photo-detector is due to the interaction between single photogenerated charges that tunnel from dot to dot and current line and we believe that each current fluctuation under light illumination is due to the charging of individual dot. It is also found that photocurrent signal depend on the light wavelength. Finally, photocurrent results performed on the photo-SET shows separately the contribution of each nanocrystals and confirm that the photo-SET acts like a single electron device. © 2010 IOP Publishing Ltd. Source


Ben Hlel D.,Institute Preparatoire Aux Etudes Dingenieurs Of Nabeul Ipein | Gaied I.,Institute Preparatoire Aux Etudes Dingenieurs Of Nabeul Ipein | Sghaier N.,Institute Preparatoire Aux Etudes Dingenieurs Of Nabeul Ipein | Sghaier N.,Lyon Institute of Nanotechnologies | And 3 more authors.
Microporous and Mesoporous Materials | Year: 2015

In this paper we will report the evolution of optical and thermal properties of thermally oxidized mesoporous silicon layers. The samples were manufactured by the conventional electrochemical anodization. The modification process including thermally oxidized samples in dry oxygen at different temperatures and duration was conducted. After treatment, the products were characterized by Spectral Reflectance in the wavelength range of 200-1100 nm which served to exclude an important decrease of the optical loss with temperature and duration of oxidation. We noticed that thermal oxidation improved the absorption of the UV light and led to a significant decrease of the average reflectivity. The band gap energy was performed by the Photoluminescence spectroscopy under an excitation at 325 nm and showed a broad emission centered at around 2.1 eV for all the samples. Furthermore, thermal conductivity and thermal diffusivity were determined by Photothermal Deflection Technique by comparing the experimental curves of normalized amplitude and phase of the photothermal signal to the corresponding theoretical ones. It was also found that the increase of both temperature and time of the thermal oxidation process affect the thermal properties of these layers. © 2014 Elsevier Inc. All rights reserved. Source


Troudi M.,University of Monastir | Sghaier N.,University of Monastir | Sghaier N.,Institute Preparatoire Aux Etudes Dingenieurs Of Nabeul Ipein | Kalboussi A.,University of Monastir | Souifi A.,Lyon Institute of Nanotechnologies
Optics Express | Year: 2010

In this paper, we analyzed slow single traps, situated inside the tunnel oxide of small area single electron photo-detector (photo-SET or nanopixel). The relationship between excitation signal (photons) and random-telegraph-signal (RTS) was evidenced. We demonstrated that photoinduced RTS observed on a photo-detector is due to the interaction between single photogenerated charges that tunnel from dot to dot and current path. Based on RTS analysis for various temperatures, gate bias and optical power we determined the characteristics of these single photogenerated traps: the energy position within the silicon bandgap, capture cross section and the position within the Si/SiO x= 1.5 interfaces. © 2009 Optical Society of America. Source


Hlel D.B.,Institute Preparatoire Aux Etudes Dingenieurs Of Nabeul Ipein | Bouzidi M.,University of Monastir | Sghaier N.,Institute Preparatoire Aux Etudes Dingenieurs Of Nabeul Ipein | Sghaier N.,Lyon Institute of Nanotechnologies | And 4 more authors.
Optik | Year: 2016

In this paper we investigate the thermal oxidation effect on optical and thermal properties of meso-porous silicon (meso-PS) layers using photoluminescence (PL) and photothermal deflection techniques (PDS, PTD). Samples have been successfully prepared by electrochemical anodization process. After a pre-oxidation for 1 h 30 min at 300 °C, layers are thermally oxidized in dry oxygen at different temperatures (800, 1000 °C) and durations. PL measurements show that the annealed layers have comparable spectra with a peak position focused on 2.1 eV. This behavior indicates the formation of luminescent silicon (Si) nanocrystallites with comparable average sizes. From the effective mass theory, the diameter of those nanocrystallites is estimated to be around 2.2 nm. Another estimation of the mean size of the silicon nanocrystallites obtained from the evolution of the thermal conductivity of the meso-PS layers based on photothermal deflection technique (PTD) data was close to the values obtained from the PL results. Photothermal deflection spectroscopy (PDS) measurements show that the thermal oxidation affects the absorption edge of the Si substrate. The optical band gap energy of the started substrates determined from the Tauc's relation is observed to increase with the thermal temperature and duration. The possible origins of this shift are discussed. © 2016 Elsevier GmbH. All rights reserved. Source


Trabelsi M.,Lyon Institute of Nanotechnologies | Trabelsi M.,Institute Preparatoire Aux Etudes Dingenieurs Of Nabeul Ipein | Militaru L.,Lyon Institute of Nanotechnologies | Sghaier N.,Institute Preparatoire Aux Etudes Dingenieurs Of Nabeul Ipein | And 2 more authors.
Solid-State Electronics | Year: 2011

This work reports on a comprehensive process of trapping centers in Silicon nanocrystal (nc-Si) memories devices. The trap centers have been studied using Random Telegraph Signal (RTS) and Low Frequency (LF) techniques. The study of the traps which are responsible for RTS noise in non-volatile memories (NVM) devices as a function of gate voltage and temperature, offers the opportunity of studying the trapping/detrapping behaviour of a single interface trap center. The RTS parameters of the devices having random discrete fluctuations in the drain current get more information about trap energy level and spatial localization from the SiO2/Si interface. The impact of trap centers has been also investigated showing the significant noise between memories and references devices. Furthermore, it has convincingly been shown that this discrete switching of the drain current between a high and a low state is the basic feature responsible for l/fγ flicker noise in MOSFETs transistors. © 2010 Elsevier Ltd. All rights reserved. Source

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