Synthesis of ultra-high-purity CdTe ingots by the traveling heater method

For telluride compounds, the presence of electrically active contaminants in the grown crystals is one of the critical factors that can severely limit the ensuing device performance. In order to minimize contamination from both precursor material handling and environmental sources during the compounding operation, a fully integrated traveling heater method (THM) CdTe synthesis process was developed. Based on glow discharge mass spectroscopy (GDMS) analysis, the average total impurity content, excluding carbon, nitrogen, and oxygen, is in the order of 100 PPB atomic, with zinc being the major contaminant and accounting for more than 40 pct of this value.