METHOD OF AVOIDING AMPOULE ADHESION OF INGOTS IN BRIDGMAN GROWTH OF CUINSE2

One of the main difficulties in growing CuInSe2 is the adhesion of the material to the inner wall of the quartz ampoule after the growth. Carbon coating on the inner wall of the ampoule was found to eliminate the adhesion problem, not by forming a barrier layer between the CuInSe2 and the ampoule, but by reducing the oxygen or water vapour inside the sealed ampoule. The carbon was only partially coated on the ampoule and had no direct contact with the CuInSe2 throughout the experiment to avoid any contamination. Addition of other gettering agents of oxygen such as Ti, Mo and graphite were also able to eliminate the adhesion problem. By adding a suitable gettering agent into the ampoules, ingots without cracks and voids were grown, and monocrystals with dimensions as large as 2 cm on a side were obtained by the horizontal Bridgman method.