A light-activated switching resistor, an optical sensor incorporating a light-activated switching resistor, and methods of using such devices

摘要

A switching resistor comprises a dielectric layer (e.g silica SiO2) disposed between a first electrode layer (e.g Silicon) and a second electrode layer (e.g ITO), the switching resistor having a high resistance state and a low resistance state. The switching resistor is responsive to a voltage bias (24 figure 2) exceeding a threshold which is applied between the electrodes, such that the bias enables a switch from a high to a low resistance state. Crucially, the switching resistor is sensitive to photo illumination (light irradiation) of the device which reduces the threshold. The first electrode may be a p-type silicon substrate absorbing photo generated free electron (free carriers) which create Frenkel pairs in the adjacent dielectric, which may be silicon oxide (SiOx). The Frenkel pair represent an oxygen vacancy and oxygen interstitial ion, the oxygen vacancy creating a conductive filament ion the dielectric layer. The second electrode is preferably comprised of Indium Tin Oxide ITO. The photo illumination is within the wavelength 300nm to 1500nm. The silica dielectric and ITO are transparent to light. The reduction in threshold due to light (photo) illumination varies from 0.1 to 0.5 V. The first electrode may comprise multiple strips. The switching resistor may be incorporated into an optical sensor. A method of operation is also included.