Texas Instruments Corporation

International Telephone and Telegraph Corporation

Shang-Yi Chiang

Yet-Zen Liu

Bernard G Carbajal

A small-area light-emitting diode of the surface-emitting type has a double heterojunction semiconductor structure grown on a substrate. A semiconductor blocking layer having a hole formed therein is disposed between the substrate and the layers of the double heterojunction semiconductor structure to confine the transverse current flow for greater efficiency. A metallic contact layer is formed on the surface of the double heterojunction semiconductor structure on the side opposite the substrate and has a registering hole formed therein having a size approximately equal to the size of the hole formed in the semiconductor blocking layer and disposed in registration therewith along an axis perpendicular to the layers. The cap layer of the double heterojunction semiconductor structure may include a hole etched therethrough and in registration with the previously mentioned holes for better light emission. In a further embodiment, the light-emitting layer is restricted in surface area to a region aligned with said holes for even greater light efficiency and current confinement.

Method of manufacturing a light-emitting diode by liquid phase epitaxy

Light emitting diode structure

An integrated, monolithic array of solar cells wherein isolation between cells permits series interconnection of the cells to provide an output voltage for the array equal to the sum of the voltages of the unit cells. Although normal PN junction isolation is ineffective when exposed to light, the present structure includes a form of junction isolation that is effective when exposed to light, or to other radiation. For example, a band of heavily doped P-type silicon, formed by thermomigration of aluminum through an N-type wafer, provides such isolation.

Integrated solar cell array

A solar cell having first and second closely spaced, parallel P-N junctions is fabricated, wherein the illuminated surface is totally free of metallization, i.e., the junction nearest the illuminated surface is not electrically connected, and thereby participates only indirectly in the collection of photo-generated carriers by providing a charge field to suppress the front surface recombination and to enhance collection at the back side junction. All metallization is on the back side, which preferably includes an interposed finger pattern of N+ and P+ zones.

Growing community of inventors

Richardson, TX, United States of America

Shang-Yi Chiang