US PATENT SUBCLASS 257 / 10
.~ Low workfunction layer for electron emission, e.g., photocathode electron emissive layer

Current as of: June, 1999
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257 /   HD   ACTIVE SOLID-STATE DEVICES (E.G., TRANSISTORS, SOLID-STATE DIODES)

9  DF  THIN ACTIVE PHYSICAL LAYER WHICH IS (1) AN ACTIVE POTENTIAL WELL LAYER THIN ENOUGH TO ESTABLISH DISCRETE QUANTUM ENERGY LEVELS OR (2) AN ACTIVE BARRIER LAYER THIN ENOUGH TO PERMIT QUANTUM MECHANICAL TUNNELING OR (3) AN ACTIVE LAYER THIN ENOUGH TO PERMIT CARRIER TRANSMISSION WITH SUBSTANTIALLY NO SCATTERING (E.G., SUPERLATTICE, QUANTUM WELL, OR BALLISTIC TRANSPORT DEVICE) {5}
10.~ Low workfunction layer for electron emission, e.g., photocathode electron emissive layer {1}
11  DF  .~.~> Combined with a heterojunction involving a III-V compound

DEFINITION

Classification: 257/10

Low workfunction layer for electron emission (e.g., photocathode electron emissive layer):

(under subclass 9) Subject matter wherein a layer of material from which electrons are emitted with less input energy than that necessary to emit them from adjacent material is provided.

(1) Note. The adjacent material and the low workfunction layer form either a heterojunction or a Schottky barrier, depending on whether both materials are semiconductors or one of the materials is a metal.

(2) Note. Typical low workfunction layer devices include cold cathode emitters in electron tubes.

SEE OR SEARCH CLASS

313, Electric Lamp and Discharge Devices,

346+, and 373+ for photoemissive cathodes and subclasses 527, 530, 541, and 542+ for photocathodes in general.

438, Semiconductor Device Manufacturing: Process,

20, for processes of making an electron emissive device utilizing a semiconductor substrate.