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X-ray study; a-Ga₂Se₃, Ga₂Te₃; air-oxidised powders

X-ray studies of the stoichiometrically prepareda-Ga₂Se₃ and Ga₂Te₃ are reported after various stages of air-oxidation in the temperature ranges 250 to 825° C and 250 to 650° C respectively. Diffractometric powder data of Ga₂Te₃ are also reported over the complete 2ϑ range with remarkable difference in the relative intensities of the (444) and (642) reflections. Ina-Ga₂Se₃ the oxidation proceeds by formation of the most stable phase, beta-gallium sesquioxide, complete oxidation occurring at 650° C. For Ga₂Te₃ a mixture of Ga₂TeO₆ and TeO₂ is obtained as the intermediate oxidation products in the range 500 to 600° C, while at 450° C some extra lines which could be indexed on the super-lattice cell of Ga₂Te₃, along with Te and unchanged Ga₂Te₃ lines, are observed. Oxidation at the higher temperature of 650° C led to the disappearance of TeO₂ lines leaving Ga₂TeO₆ as the final well-crystallised phase.

A K Mukherjee¹ U Dhawan¹ K D Kundra¹ S Z Ali¹

1. National Physical Laboratory, Hillside Road, New Delhi - 110 012

Published

January 1980

Manuscript received

5 November 1979