Claims
- 1. A photo-responsive device, comprising:
- a gallium arsenide substrate (12) having an n+ type majority charge carrier concentration and a pair of opposed surfaces (14, 18);
- an epitaxial layer (16) of gallium arsenide having an n type majority charge carrier concentration formed upon a first of said surfaces;
- first means (20) disposed upon a second of said surfaces for providing electrical contact with said substrate;
- a thin, transparent insulating layer (24) of an oxide covering said epitaxial layer;
- a thin, transparent layer (28) of a refractory metal deposited upon said layer of oxide;
- a thin, transparent layer (30) of a noble metal deposited upon said refractory metal layer;
- said refractory metal having a high thermionic work function approximating that of said noble metal; and
- second means (32) disposed upon said noble metal layer for providing electrical contact with said noble metal.
- 2. The device of claim 1 wherein said refractory metal layer has a thickness of less than forty angstrom units.
- 3. The device of claim 1 wherein said refractory metal layer comprises molybdenum.
- 4. The device of claim 1 wherein said refractory metal layer comprises nickel.
- 5. A method of making a photo-responsive device, comprising the steps of:
- growing an epitaxial layer (16) of gallium arsenide having an n type charge carrier concentration upon a first surface of a substrate (12) of gallium arsenide having an n+ type charge carrier concentration and a second surface opposed to said first surface;
- applying an ohmic contact (20) to said second surface;
- forming a thin, transparent insulating layer (24) of an oxide upon said epitaxial layer;
- depositing a thin, transparent layer (28) of a refractory metal upon said layer of oxide;
- depositing a thin, transparent layer (30) of a noble metal upon said refractory metal layer having a high thermionic work function approximating that of said refractory metal; and
- forming an ohmic contact (32) upon said thin layer.
- 6. The method of claim 9 wherein said refractory metal layer is deposited to a thickness of not more than forty angstrom units.
- 7. The method of claim 5 wherein said refractory metal layer comprises molybdenum.
- 8. The method of claim 5 wherein said refractory metal layer comprises nickel.
ORIGIN OF THE INVENTION
The invention described herein was made by an employee of the United States Government as well as in the performance of work under a NASA Contract and is subject to the provisions of Section 305 of the National Aeronautics and Space Act of 1958, Public Law 85-568 (72 Stat. 435; 42 U.S.C. 2457) and accordingly may be manufactured and used by or for the Government for governmental purposes without the payment of any royalties thereon or therefor.
US Referenced Citations (14)
Foreign Referenced Citations (2)
Number |
Date |
Country |
56-133881 |
Oct 1981 |
JPX |
1426395 |
Feb 1976 |
GBX |
Non-Patent Literature Citations (3)
Entry |
P. Sircar et al., Canadian J. Phys., vol. 59, pp. 716-717, (1981). |
K. A. Pandelisev et al., J. Appl. Phys., vol. 53, pp. 720-723, (1982). |
W. A. Anderson et al., Solid State Electronics, vol. 19, pp. 973-974, (1976). |