Novel investigations on thermogravimetric and differential thermal analyses of elemental, compound and mixed semiconductors

Abstract

A systematic study was made of the relative stability and various phase changes which take place when elemental compound and mechanically mixed semiconductors are heated. Those were chalcogens, calcogenides and mixtures of the two. The interest in the present investigation is due to the useful application of the prepared materials in the transistor, radar, rectifier and other electronic industries. Thermogravimetry and differential thermal analysis were carried out in air in the temperature range 20-830 '. The results led to the conclusion that thedegree of stability of the mechanically mixed semiconducting components is much higher than that of either elemental or compound semiconductors. The results were discussed on the basis of the eiectronegativity differences and oxygen affinities of the non-metallic components. The thermal stability ranges were evaluated in each case for the materials investigated, for their subsequent physical measurements and their suitability for the production of semiconducting devices.TG and DTA have opened up new possibilities for investigations of the synthesis of semiconducting materials. They are used to study for example the following features:!) Direct synthesis of semiconductor materials from their constituents.2) Kinetics of phase equilibration. AntimonyIt was earlier found [1,2] that molten antimony is oxidized on heating in air (-~800~ This method was used for the preparation of antinomy trioxide. SulphurIt was previously noticed [3] that, when sulphur is heated in air, it does not lose weight till 135". Above this temperature, the combustion of sulphur follows smoothly, with weight loss. At 256 ~ the container is completely empty of sulphur.