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Patent Issued for III-V Nanoparticles and Method for Their Manufacture

July 2, 2014



By a News Reporter-Staff News Editor at Journal of Engineering -- From Alexandria, Virginia, VerticalNews journalists report that a patent by the inventors Strupeit, Tim (Hamburg, DE); Weller, Horst (Hamburg, DE); Kornowski, Andreas (Hamburg, DE), filed on September 19, 2008, was published online on June 17, 2014.

The patent's assignee for patent number 8753592 is Centrum fur Angewandte Nanotechnologie (CAN) GmbH (Hamburg, DE).

News editors obtained the following quote from the background information supplied by the inventors: "Methods for the manufacture of III-V semi-conducting particles, such as indium phosphide, are known in the literature. For example, U.S. Pat. No. 4,783,320 (Adamski et al, assigned to the United States of America as represented by the Secretary of the Air Force) teaches a process for the high pressure synthesis of InP using an independent temperature control of a three zone furnace incorporating a heat pipe that provides a stable temperature profile throughout the synthesis cycle. This apparatus and method disclosed in the U.S. Pat. No. 4,783,320 teaches the manufacture of InP by directly reacting the elements Indium (In) and Phosphorus (P) in the furnace at temperatures above 800.degree. C.

"U.S. Pat. No. 4,185,081 (Fauth et al, assigned to the United States of America as represented by the Secretary of the Air Force) teaches a method for manufacturing InP which is similar to the method taught in the Adamski U.S. Pat. No. 4,783,320. The U.S. Pat. No. 4,185,081 discloses the direct reaction of the elements In and P in a controlled apparatus. The apparatus utilises specific heating, cooling and pressurising to safely produce InP.

"UK patent application GB2356395 (Venezia Tecnologie S.p.A) discloses a further method for the direct manufacture of InP, whereby the elements In and P are directly reacted in a closed system at temperatures above 1000.degree. C. and a pressure of 1850-2000 bars with a constant temperature increase relevant to time.

"International Patent Publication No. WO/2006/099386 (Massachusetts Institute of Technology) discloses a method for the manufacture of colloidal III-V nanoparticles. The method of manufacture comprises reacting a solution of comprises at least one source material including a group III element with a source material. The source material includes including a group V element and a reducing agent in a solvent. The solvents used in the manufacturing methods disclosed in this patent application are not high boiling solvents. The manufacture of the III-V nanoparticles is conducted at high pressures in sealed containers.

"In the literature there are a number of references to the manufacture of III-V semi-conductor compounds. For example. Micic et al 'Synthesis and Characterisation of InP. GaP and GaInP.sub.2, J. Phys. Chem. 1995, 99, 7754-7759, discloses a method for the manufacture and characterisation of InP, GaP and GaInP.sub.2 quantum dots. This document discloses a method for the manufacture of InP by mixing a chloro-indium oxalate complex with P(SiMe.sub.3).sub.3 in a molar ratio of In:P 1.6:1. The authors utilise trioctylphosphine oxide (TOPO) and trioctylphosphine (TOP) in this manufacture method.

"Malik et al in 'Gallium Arsenide Nanoparticles: Synthesis and Characterisation', J. Mater. Chem., 2003, 13, 2591-2595, disclose the manufacture of GaAs nanoparticles from GaCl.sub.3 and As(NMe.sub.2).sub.3, by slowly heating at 167.degree. C. for 7 days. The P(SiMe.sub.3).sub.3 compounds used in this publication are highly explosive and inflammable as well as being relatively expensive.

"None of the prior art discloses a simple method for the manufacture of III-V particles as disclosed herein."

As a supplement to the background information on this patent, VerticalNews correspondents also obtained the inventors' summary information for this patent: "The present invention discloses a method for the manufacture of III-V compounds. Examples of the III-V compounds are used in semi-conductors. The method for manufacturing the III-V compounds comprises; reacting a solution containing at least one source material including a group III element and a source material including a group V element. The reaction is conducted in a high boiling point solvent. The reaction is conducted in an inert atmosphere and at atmospheric pressure. The high boiling point solvent comprises a stabiliser and a reducing agent. The reaction is conducted for a predetermined period of time and at a predetermined temperature. The manufactured III-V compound is precipitated from the high boiling point solvent and isolated.

"In an aspect of the present invention, the solution of the high boiling point solvent and the stabiliser as well as the group V source is a solution of trioctylphosphine oxide and trioctylphosphine (TOPO/TOP). The trioctylphosphine oxide and trioctylphosphine (TOPO/TOP) has the advantage that no additional group V element (where the product is a III-P compound) is required.

"After the reaction is complete the manufactured III-V compound is precipitated from the reaction solution by the addition of a polar organic liquid. The polar organic liquid includes, but is not limited to methanol, ethanol, propanol or acetone. The manufactured III-V compound is centrifuged and filtered from the reaction solution. The manufactured III-V compound is further purified by being re-dissolved in a non-polar organic liquid such as toluene and precipitated from the resultant solution by the addition of a polar organic liquid. The manufactured III-V compounds are then filtered and isolated. The purification process may be repeated a number of times.

"The predetermined temperature for the reaction to progress for the manufacture of the III-V compounds is from 100.degree. C. to above 350.degree. C. The predetermined time period for the reaction to go to completion is from 1 to 30 hours.

"The source material for the group III compound can be selected from a group consisting of a group III salt, a group III oxide or a group III acetate. The source material for the group V compound can be a II-V compound, whereby the group II-V compound is selected from a group consisting of Ca.sub.3P.sub.2 or Mg.sub.3As.sub.2. The source material for the group V compound can also be triphenylphosphine (PPh.sub.3). This can also be used as the high boiling point solvent in the method for manufacture.

"For the method for manufacture to proceed effectively the high boiling point solvent contains a stabiliser. The stabiliser includes but is not limited to trioctyl-phosphine/trioctylphosphine oxide. The stabiliser can also be a long chain amine. The stabiliser can also be a mixture of trioctylphosphine/trioctylphosphine oxide and the long chain amine.

"The high boiling point solvent also contains a reducing agent. The reducing agent is a Lewis base. The reducing agent includes, but is not limited to butyl-lithium (Buli) or potassium borohydride.

"The materials used in this method of manufacture are all reasonably inexpensive. The materials and equipment used in this method of manufacture are easily accessible. This method for the manufacture of III-V compounds provides a cheaper and less hazardous method for than the methods for manufacture disclosed in the prior art."

For additional information on this patent, see: Strupeit, Tim; Weller, Horst; Kornowski, Andreas. III-V Nanoparticles and Method for Their Manufacture. U.S. Patent Number 8753592, filed September 19, 2008, and published online on June 17, 2014. Patent URL: http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=8753592.PN.&OS=PN/8753592RS=PN/8753592

Keywords for this news article include: Nanoparticle, Reducing Agents, Emerging Technologies, Indicators and Reagents, Centrum fur Angewandte Nanotechnologie.

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Source: Journal of Engineering


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