The Effect of Adsorbed Molecules on the Charge-Carrier Spectrum in a Semiconductor Nanowire

Abstract

A semiconductor quantum nanowire with adsorbed organic molecules is considered. It is shown that a shift of the quantum-confinement levels in the wire includes both a linear contribution (determined by the orientation of the molecular dipoles and the sign of the charge carrier) and a nonlinear contribution (determined by the deformation of the molecular layer). In the case of a long nanowire, longitudinal quantization of the charge carriers is described self-consistently by a nonlinear Schrodinger equation with boundary conditions. For all values of the nonlinear-interaction parameter, the spectrum is determined by a set of transcendental equations. It is shown that the role of nonlinear interaction is greater for lower energy levels and increases with an increase in the mass of the charge carriers and decrease in the rigidity of the molecular layer. Carrier localization, which manifests itself in the experiment as an increase of the resistance, is possible. The processes considered may be important in relation to chemisorption sensors, chips based on nanotubes and DNA, and other structures with adsorbed organic layers.