Lucent Technologies Inc.

At&t Bell Laboratories

Lawrence Seibles

Sungho Jin

Wei Zhu

Gregory Peter Kochanski

James W Mitchell

Michael Philip Bohrer

Po-Yen Lu

Guang-kai David Jeng

The invention relates to a system and method for the recovery of germanium from the Modified Chemical Vapor Deposition (MCVD) processing wastes by chemical conversion and recovery of germanium from the solid cake product. In the present method, the direct reaction of gaseous hydrogen chloride with the recovered materials effects the rapid and complete chlorination of the germanates, yielding germanium tetrachloride. The germanium tetrachloride product is completely volatilized and removed from the mixture during the exothermic process.

Process for the direct production of germanium tetrachloride from hydrated germanate-containing solids using gaseous hydrogen chloride

Applicants have discovered methods for making, treating and using diamonds which substantially enhance their capability for low voltage emission. Specifically, applicants have discovered that defect-rich diamonds--diamonds grown or treated to increase the concentration of defects--have enhanced properties of low voltage emission. Defect-rich diamonds are characterized in Raman spectroscopy by a diamond peak at 1332 cm.sup.-1 broadened by a full width at half maximum .DELTA.K in the range 5-15 cm.sup.-1 (and preferably 7-11 cm.sup.-1). Such defect-rich diamonds can emit electron current densities of 0.1 mA/mm.sup.2 or more at a low applied field of 25 V/.mu.m or less. Particularly advantageous structures use such diamonds in an array of islands or particles each less than 10 .mu.m in diameter at fields of 15 V/.mu.m or less.

Field emission devices employing enhanced diamond field emitters

In contrast to previous approaches, the present inventors have discovered that diamond films can be grown by carbon CVT reactions occurring exclusively in the exothermic regime, where the lower temperature (&lt;1500.degree.C.) conditions considerably simplify the equilibrium gas phase chemistry. Under these conditions of a small temperature gradient and short transport distance between the source and substrate, supersaturation of the gas phase with regard to graphite and diamond does not attain sufficiently high values to induce spontaneous homonucleation of graphite and diamond in the gas phase. With this process, temperatures as low as 680.degree.C. were found to be sufficient to induce the growth of continuous diamond films free of non-diamond allotropes.

Method for growing continuous diamond films

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Piscataway, NJ, United States of America

Lawrence Seibles