Opto-electronic gas sensor

Claim 1

A semiconductor device adapted for operation as a gas sensor, comprising: a body of semiconductor material including a substrate region and a multiple quantum well (MQW) structure over said substrate region, said MQW structure having first and second different materials arranged alternately in a plurality of parallel planar layers in a vertical direction, said planar layers exhibiting an absorption edge for electromagnetic radiation at a first wavelength thereof and having a respective predetermined relatively thin thickness dimension of a value wherein an electric field acting perpendicularly to said planar layers causes a shifting of said absorption edge from said first wavelength of said electromagnetic radiation to a second wavelength of said electromagnetic radiation; a layer of a transition metal formed over a topmost layer of said MQW structure, said layer of a transition metal having a relatively thin thickness dimension being substantially transparent to the electromagnetic radiation and substantially permeable to a gas to be detected; and a light detector, located below said substrate region, for detecting the sifting in wavelength of said electromagnetic radiation transmitted in the vertical direction through said layer of transition metal, said MQW structure, and said substrate region, wherein said layer of transition metal allows gas atoms to permeate into the topmost layer of said MQW structure so as to form a dipole layer resulting in an electric field acting perpendicularly to said planar layers of said MQW structure, thereby causing a shifting in wavelength of said electromagnetic radiation which is detected by said light detector to indicate the presence of the gas.