Ahmed Bouhekka

• Professor at Tissemsilt university

The purpose of this experimental and modeling research is to study the pH effect and to determine the surface coverage plus the adsorption constant (Ka) of bovine serum albumin (BSA) protein adsorbed on TiO2 anatase surface, respectively. In situ Fourier transform infrared-attenuated total reflection spectroscopy in a flow-through cell was used to...

The aim purpose of the present work is highlighting the impact of surface oxygen vacancies and H2O flux on the behavior of water adsorption at the rutile titanium dioxide (110). Therefore, a theoretical model, based on molecular and dissociation mechanisms at different surface atomic sites, was formulated in a system of partial differential coupled...

In this work, we focus on the effect of H2O flux and temperature on the behaviour of water molecules at rutile (110) face. To achieve this goal; we converted the deferent ways of H2O on surface to a system of nonlinear differential equations based on the Langmuir equation. The results showed that H2O flux has a strong influence on the dissociation...

The aim purpose of this work is to study the fundamental potential effect of circular crystalline silicon pillars gratings on the enhanced near infrared light trapping. Gratings with periods of 1.2, 1.5 and 1.8 μm and depth of 400 nm were located on the rear side of the wafers. The findings of this investigation clearly indicated that the gratings...

Hydrogenated nanocrystalline silicon, while being non-charged and non-polar, could be an ideal candidate for the non-covalent and orientation-controlled immobilization of biomolecules thanks to local electric fields around nanocrystals. To that effect, the adsorption of bovine serum albumin on substrates with different densities of nanocrystals, re...

Highly crystallized hydrogenated silicon layers were obtained via the treatment of hydrogenated polymorphous silicon films in a molecular hydrogen ambient. This contrasts other postdeposition studies that obtained nanocrystalline silicon films but necessitated either a plasma activation or high-temperature annealing. The structure of the samples wa...

The main objective of the present work is to study experimentally and by simulation, using the one dimensional analysis of microelectronic and photonic structures program (AMPS-1D), the correlation between the crystalline volume fraction (Fc) and the transport properties of hydrogenated microcrystalline silicon thin films (μc-Si:H). The Fc was dete...

In the present work, three series of hydrogenated silicon thin films were prepared by radiofrequency magnetron sputtering method at low temperature, various deposition pressures (2, 4, 6 Pa) and different rf powers (200, 300, 400, 500 W) while all the other plasma parameters were fixed. The deposited films were characterized using atomic force micr...

The adsorption of Bovine Serum Albumin (BSA) proteins on amorphous silicon (a-Si) surfaces was studied with respect to solution pH. Thin films of a-Si were deposited using radio-frequency magnetron sputtering at room temperature and then treated in a hydrogen ambient to form a hydrogenated a-Si surface layer (a-Si:H). The interactions of the as-dep...

We study the effect of amorphous silicon (a-Si) surface hydrogenation on Bovine Serum Albumin (BSA) adsorption. A set of (a-Si) films was prepared by radio frequency magnetron sputtering (RFMS) and after deposition; they were treated in molecular hydrogen ambient at different pressures (1-3 Pa). Fourier transform infrared attenuated total reflectio...

We study the effect of amorphous silicon (a-Si) surface hydrogenation on Bovine Serum Albumin (BSA) adsorption. A set of (a-Si) films was prepared by radio frequency magnetron sputtering (RFMS) and after deposition; they were treated in molecular hydrogen ambient at different pressures (1–3 Pa). Fourier transform infrared attenuated total reflectio...

By using a polyelectrolyte layer gold nanoparticles have been assembled onto a Ge internal reflection element. Upon illumination with visible and near infrared light a strong infrared absorption has been observed, which can be traced to intervalence band transitions in Ge. This reveals the existence of holes in the Ge near its valence band edge. Th...

A Fourier transform infrared-attenuated total reflection (FTIR-ATR) spectroscopy study of the photodegradation of adsorbed bovine Serum Albumin (BSA) on porous TiO2 films was carried out. The experiments were performed in a flow-through cell in water at concentrations of 10-6 mol/L at room temperature. The curve fitting method of the second derivat...

In this work in situ Fourier transform infrared-attenuated total reflection (FTIR-ATR) spectroscopy in a flow-through cell was used to study the effect of visible light irradiation on bovine serum albumin (BSA) adsorbed on porous TiO2 films. The experiments were performed in water at concentrations of 10−6 mol/l at room temperature. The curve fitti...

A Monte-Carlo simulation of the growth of hydrogenated amorphous silicon (a-Si:H) thin films deposited by plasma enhanced chemical vapour deposition technique is presented in this work which is based on four fundamental processes that determine the layer growth: (i) random deposition of SiH3 radicals, (ii) desorption, (iii) “H” abstraction and (iv)...

Microcrystalline silicon has its own macroscopic characteristics which are different from each of the single phase characteristics. Hence, each phase of µc-Si:H plays an important role in electronic transport. In this paper, we model a basic Schottky structure with a 1 µm thick, the device considered in our study is an alternance of amorphous and c...