DETECTION OF BIOSURFACTANTS ON THE SURFACE OF NANOPOROUS SILICON

Abstract

Aim. The investigation of the interaction of certain natural and semi-synthetic surfactants with the surface of semiconductor structures based on nanoporous silicon (nano-PC). Methods. The samples of nano-PS with a high doping level (KC-0.01) were obtained by anodic electrochemical etching of single-crystal silicon in an electrolyte on the basis of 48% aqueous solution of hydrofluoric acid. The low contact resistance was determined by annealing (450 °C) of the samples of nano-PS with aluminum contacts deposited on them. The detection was carried out for biosurfactants: sarcosyl (sodium lauryl sarcosine), ramolipid (rhamnozide β-hydroxydecanoic acid) and cycloheptadecanoic acid. Results. The interaction of biosurfactants with the surface of nano-PC was studied. It is shown that these compounds significantly influence the volt-ampere characteristics of nano-PC samples. Within the framework of the adsorption model, the interaction of the investigated surfactants with nano-PC is explained. The change in current-voltage characteristic (СVC) samples of nano-PC during the deposition of supramolecular objects is associated with the filling of nanopores with these macromolecules possessing a significant dielectric constant. It is shown that the effect of the surfactants studied on the electrical parameters of nano-PC has the characteristic features for each of the compounds studied, which allows differentiating the different surface-active substances differentially on the basis of nano-PC. Conclusion. The physical reason for the change in the I–V characteristics of nanoPC samples during application of biosurfactants is related to the filling of nanoPS with multilamellar surfactant structures. The complex form of the CVC for the adsorption of sarcosyl, rhamnolipid, cycloheptadecanoic acid is determined by heterojunctions between planar aluminum contacts and silicon nanostructures, and changes in the region of microballoons formed between filamentary crystals of the surface of the nano-PC.