ON THE ADHESION OF IN0.2GA0.8SB TO QUARTZ AMPOULE DURING SYNTHESIS

In0.2Ga0.8Sb has been synthesized and polycrystals have been grown by the Vertical Bridgman technique. Sticking of ingot to the quartz ampou le and ampoule cracking have been found to be major problems. The pres ence of native oxides on the surface of the starting material impedes the formation of homogeneous compounds due to which the structural qua lity of the ingots is poor. Worst sticking is observed with improper h omogeneization and when excess of pure indium is present on the surfac e of the crystal. Several procedures have been adopted to avoid sticki ng and cracking. The most efficient way of solving this problem is to employ a high-temperature baking in dynamic Vacuum prior to synthesis by placing the ampoule in a region of the furnace with a temperature g radient. The post-baking cooling rate is also extremely critical to av oid cracking. The polycrystalline alloy thus formed by adopting the pr e-synthesis baking cycle shows better homogeneity and structural quali ty.