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Browse Prior Art Database

Silicon Light Emitting Devices

IP.com Disclosure Number: IPCOM000079593D
Original Publication Date: 1973-Aug-01
Included in the Prior Art Database: 2005-Feb-26
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Brodsky, MH: AUTHOR

Abstract

Metastable forms of silicon are suggested as candidates for making PN junctions capable of emitting light, or for being useful as high hand gap junction materials.

This text was extracted from a PDF file.
This is the abbreviated version, containing approximately 80% of the total text.

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Silicon Light Emitting Devices

Metastable forms of silicon are suggested as candidates for making PN junctions capable of emitting light, or for being useful as high hand gap junction materials.

Normally, silicon is a poor choice for use as a light-emitting diode material, because it has an indirect band gap of only one electron volt and, as such, would not make a practical material for use in a photoluminescent or cathodeluminescent device. GaAs, GaP, SiC, and the like, are efficient and useful as materials for making light-emitting devices, but they are not as universally used or understood as silicon is.

It is believed that certain metastable polymorphs of silicon have a direct band gap near 1.8 electron volts, therefore making them economically eligible for use as PN junction materials. To achieve the desired PN characteristics, ordinary silicon, crystalline and having a diamond lattice structure is employed. The silicon, after doping to make a PN junction, is subjected to a temperature- pressure cycle sufficient to transform the crystalline material into another 4-fold coordinated crystal structure, e.g., an 8 atom per unit cell, body-centered cubic structure, or a 12 atom per unit cell with simple tetragonal structure. Such a temperature-pressure cycle is described in an article "Phase Diagrams of Si and Ge to 200K bar, 1000 Degrees C" by F. R. Bundy in the Journal of Chem. Phys. 41, p. 3809 (1964).

Since such treated silicon has each of its atoms 4-fold co...