New Class of Chemical Sensors for Gases Based on Photoluminescence from Semiconductor-Derived Interfaces

摘要

The photoluminescence (PL) of semiconductors can be perturbed by exposure of the solid to gases. These physicochemial interactions occurring at the semiconductor surface can be exploited to create a new class of chemical sensors. For homogeneous semiconductors, a dead-layer model has been used to correlate changes in PL intensity with variations in the depletion width W caused by the gas. A graded n-CdSxSe1-x substrate permits modulation of the PL spectral distribution by gases and is color-coded to permit PL changes to be correlated with variations in the effective electric field present in the solid. Three semiconductors that have been chemically derivatized with ferrocene can sense volatile oxidants and reductants; and etched semiconductors can respond to sulfur dioxide and ammonia, presumably through acid-base interactions. All of the structures lend themselves to device fabrication by use of optical fiber technology. Keywords: Photoluminescence; Dead-layer model; Depletion width; Surface recombination velocity; Chemical sensors, Hydrogen, Ammonia, Sulfur dioxide, Iodine, Hydrazine, and Cadium compounds.