Multilayered slant-angle thin film energy detector

A detector of thermal energy is composed of an insulating substrate such as glass or sapphire coated with a thin film deposit of a slant-angle deposited metal preferably a transition element such as Ti, V, Cr, Co, Ni, Ta, W, U, Os, Ir, Pt and Mb exhibiting a transverse thermoelectric effect in response to a thermal energy gradient normal to the plane of the deposit. A layer of an electrical insulating material which is thermally conductive is deposited upon the thin film deposit, using materials such as SiO.sub.2, SiO, perylene, etc. Another thin film deposit of a slant-angle film is deposited on top of the insulating material. A stack of alternate slant-angle thermoelectric elements and electrical insulating layers is formed to a depth at which the thermal gradient in the lowest slant-angle deposit is marginally advantageous. An input light, laser or other heat producing beam is applied to the upper layer of the stack. Alternatively, heat can also be applied to the lower surface through a transparent substrate producing interfacial heating. Heat leaks into other film layers producing a substantial thermal gradient and hence, a thermoelectric transverse voltage in each of the metal films. The layers are interconnected electrically.




DETAILED DESCRIPTION In accordance with this invention a substrate of a thermally conductive dielectric material, is coated with a first thin film deposit of an electrically and thermally conductive material having an induced anisotropy.
A second thin film deposit of electrically insulating, thermally conductive material is applied to the exposed surface of the first deposit.
A third thin film deposit of electrically and thermally conductive material having an induced anisotropy overlies the second deposit.
The first and third thin film deposits are connected electrically to at least a pair of contacts for developing a transverse electrical signal (voltage) between the contacts.
There are means applied to the structure for establishing a temperature gradient in the layers of deposits normal to the planes of the surfaces of the deposits.
Preferably, the electrically conductive material is a metal.
Such a metal should be high in melting point and be included in the transition metal group.
Appropriate metals include titanium, vanadium, chromium, cobalt, nickel, iron, tantalum, tungsten, uranium, osmium, indium, platinum, and molybdenum.
Further in accordance with this invention, the temperature gradient is supplied by means for locally directly heating a surface, which means for heating can be a laser, an electron beam or any other source of radiation producing phonons.
Further in accordance with this invention, the electrically conductive thin film deposits are composed of slant-angle deposited metallic films providing a transverse thermoelectric voltage when a thermal gradient is applied preferably at a normal angle to the plane of the films.
An object of this invention is to provide a highly efficient thermoelectric detector responsive to thermal energy gradients applied normal to the exposed surface of the detector.
Another object is to provide a more sensitive detector operable in high temperature environments and when exposed to high levels of energy.
Still another object is a more sensitive detector sensitive to electromagnetic energy from 0