Procedure for the synthesis of stoichiometric proportioned indium phosphide

Claim 1

In a method for synthesizing highly pure stoichiometric porportioned, polycrystalline indium phosphide comprising the steps of: I. providing a reaction vessel having (1) a vaporization zone, (2) a reaction zone, and (3) a constricted, interconnecting, vapor transport passageway positioned therebetween; II. placing a solid sample of red phosphorus in said vaporization zone and a solid sample of indium in said reaction zone; III. heating the vaporization zone to a temperature and pressure sufficient to vaporize said red phosphorus and effect its transport to said reaction zone; IV. simultaneously heating said reaction-zone to melt said indium and effect a reaction between said phosphorus vapors and said molten indium; V. maintaining said temperatures for a period of time sufficient to complete said reaction and produce a stoichiometric proportioned, reaction product therefrom; and VI. cooling said reaction product and removing said product from said reaction vessel, the improvement which comprises the steps of: (a) heating said vaporization zone to a temperature of 546° C. and a resulting vapor pressure of 27.5 atmospheres, (b) heating said reaction zone to a temperature between a range of 1070° C. and 1150° C. and maintaining the entire reaction zone within said temperature range during the entirety of said reaction; (c) cooling the temperature of said reaction product from its maximum to a temperature between 950° and 1000° C. at a programmed variable cooling rate ranging from 50° C. per hour to 150° C. per hour; while simultaneously maintaining the temperature at the red phosphorus interface at 546° C. (d) simultaneously cooling the temperature of both the reaction product and the red phosphorus at programmed, variable cooling rates ranging from 60° C. per hour to 150° C. per hour and 90° C. per hour to 180° C. per hour, respectively; (e) continuing said programmed cooling until the temperature of the red phosphorus reaches about 380° C. and the indium phosphide reaches about 750° C., respectively; and (f) further cooling said red phosphorus and indium phosphide in situ to room temperature.