Surface modification of p-Si by a polyethylenimine coating: influence of the surface pre-treatment. Application to a potentiometric transducer as pH sensor

Electric isolation of porous silicon by electro generated polyethyleneimine film, comparison to thermal oxide

“…2 are similar to the one obtained for EDA at a p-Si electrode [14] and for EDA at a Pt electrode [6,7]. During the first scan, one notes a peak at a potential around 2.5 V versus SRE and a flat signal ''plateau'' which takes place at potentials higher than 4 V versus SRE.…”

“…The mean sensitivity is found to be 62 mV per pH unit. Such sensitivity is quite large compared than that obtained with plane passivated silicon electrode which was close to 45 mV per pH unit [13,14] and greatly higher than that of thermal silica which has sensitivity lower than 36 mV per pH unit [23].…”

“…., by polyethyleneimine (PEI) through anodic oxidation of ethyleneimine (EDA) or diethylenetriamine (DETA) charged with salts such as Lithium Triflate (LiSO 3 CF 3 ), can give rise to a surface coating by the linear polyethyleneimine (L-PEI), through a mechanism previously described [6,7]. The PEI is used widely in chemical sensing [8 -12], most applications using PEI are determined by its pH sensitivity [13,14] and its ability to form complexes with anionic polyelectrodes [15] and with metal ions [16]. Besides, this polymer has been widely used in a number of immobilization processes of biosystems [17 -21] for its high concentration of amino groups.…”

“…Recently, coated p-Si electrodes with PEI, is used as a pH sensitive film for potentiometric transducer, and the influence of different surface treatment of p-Si has been examined [14].…”

Ultrathin polytyramine films by electropolymerisation on highly doped p-type silicon electrodes

“…However, ultrathin films of organic polymers are considered an attractive alternative approach for modification of silicon surfaces [5]. Organic films on silicon can serve as an effective etching barrier, yield chemical and mechanical protection, alter the chemical and electrical properties of the underlying surface, reveal new properties such as conductivity, photo-and electroluminescence, and provide new pathways to functionalisation of silicon for molecular recognition and sensing devices [6,7].…”