On the mechanism of spectral selective sensitivity of photonic biosensors

Abstract

We report a new optical sensor exploiting the innovative operation principle developed for the selective registration of UV and visible radiations. The operation is based on the mutual influence of depletion regions in the photovoltaic structure composed by Schottky barrier and n-p junction. The important feature of this structure is that the depletion regions expand over the whole base so that they contact each other. We have shown that the position of the contact point in the base is a function of voltage applied to the structure. Also absorption spectrum for each of the depletion regions and the photoresponse of the structure are functions of the applied voltage. We have revealed that the change induced by the applied voltage in the photoresponse, Delta I, is proportional to the change Delta lambda induced in the spectrum, Delta lambda-Delta I. This linear correlation between Delta I and Delta lambda is a very important spectrophotometric property required for the precise selective registration of bio signals in dynamic and static biological processes. (C) 2009 Elsevier B.V. All rights reserved.