Catoptrical opto-electronic gas sensor

• US 5,107,316 A
• Filed: 12/28/1989
• Issued: 04/21/1992
• Est. Priority Date: 12/28/1989
• Status: Expired due to Term

• Current Assignee: Siemens Corporate Research Incorporated (Siemens AG)
• Original Assignee: Siemens Corporate Research Incorporated (Siemens AG)
• Inventors: Colvard, Carl, Jelley, Kevin W.
• Primary Examiner(s): LARKINS, WILLIAM
• Application Number:
  US07/458,031
• Time in Patent Office: 845 Days
• Field of Search: 357/4, 357/16, 357/25, 357/30
• US Class Current: 257/432
• CPC Class Codes: G01N 2021/3192 Absorption edge variation is measured
• CPC Class Codes: G01N 21/783 for analysing gases
• CPC Class Codes: G01N 2201/067 Electro-optic, magneto-optic, acousto-optic elements

Abstract

Apparatus for detecting the presence of a gas in an ambient atmosphere comprises a multiple quantum well structure; a thin layer of a transition metal formed on the multiple quantum well structure; and an arrangement for monitoring the transmission of electromagnetic radiation sent through the multiple quantum well structure and reflected back therethrough by the thin layer.

Claims

1. A semiconductor device adapted for operation as a gas sensor, comprising:

a body of a semiconductor material including a substrate region and including a superlattice region over said substrate region, said superlattice region having first and second different materials arranged alternately in a plurality of parallel planar layers, 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 said absorption edge to shift to a second wavelength of said electromagnetic radiation;

a layer of a transition metal over said superlattice region, said layer of a transition metal having a relatively thin thickness dimension and being sufficiently thin so as to be substantially permeable to a gas; and

means for reflecting back electromagnetic radiation transmitted towards said layer of transition metal through said superlattice region.

2. A semiconductor device is recited in claim 1, wherein said layer of a transition metal is sufficiently thick as to substantially reflect said electomagnetic radiation.

3. A semiconductor device as recited in claim 1, wherein said first material is aluminum gallium arsenide (Al_x GaAs_1-x) and said second material is gallium arsenide (GaAs).

4. A semiconductor device as recited in claim 3, wherein said layer of a transition metal is of palladium.

5. A semiconductor device as recited in claim 1, wherein said substrate region has at least a portion thereof removed for providing a clear passage for said electromagnetic radiation.

6. A semiconductor device as recited in claim 4, wherein said substrate region has at least a portion thereof removed for providing a clear passage for said electromagnetic radiation.

7. A semiconductor device as recited in claim 4, wherein said layer of a transition metal is formed on a final layer of said superlattice region, said final layer being of aluminum gallium arsenide.

8. A semiconductor device as recited in claim 1, wherein said electromagnetic radiation is light, including fiber optic means for coupling light to and from said superlattice region.

9. A semiconductor device as recited in claim 8, wherein said fiber optic means comprises a fiber for incoming light and a fiber for outgoing light.

10. A semiconductor device as recited in claim 8, wherein said light is coupled to an interface at the Brewster angle.