アンモニア-アルカリ性水溶液からのCdTe電析に及ぼす電解液組成の影響 [in Japanese] The Effect of Electrolyte Composition on the Electrodeposition of CdTe from Ammonia-alkaline Solutions [in Japanese]
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Electrodeposition of CdTe from a variety of CdSO<sub>4</sub>-TeO<sub>2</sub>-NH<sub>3-</sub>(NH<sub>4</sub>)<sub>2</sub>SO<sub>4</sub> aqueous solutions was studied to determine optimum conditions for crystalline CdTe deposition. The deposit obtained from an electrolyte whose Cd (<b>II</b>)/Te (<b>IV</b>) concentration ratio was 1, showed an amorphous structure and tellurium-rich composition. Polycrystalline CdTe was obtained by partial oxidation of Te (<b>IV</b>) to Te (<b>VI</b>) in the solution, suppressing Te deposition, and by a decreasing the total ammonia concentration, accelerating Cd deposition. In electrodeposition at a cathode potential of -0.80V vs SHE and a total ammonia concentration of 5kmolm<sup>-3</sup>, polycrystalline CdTe was obtained at a Cd (<b>II</b>)/Te (<b>IV</b>) concentration ratio of 25 to 4. Particularly at a Cd (<b>II</b>)/Te (<b>IV</b>) concentration ratio of 3, the deposit showed high crystallinity, although Cd codposition was observed. Increasing the cathodic potential from -0.80V to -0.70V vs SHE and keeping the Cd (<b>II</b>)/Te (<b>IV</b>) concentration ratio at 3, suppressed Cd codposition. These results suggest that a polycrystalline CdTe single phase is obtained by controlling the cathodic potential and the Cd (<b>II</b>)/Te (<b>IV</b>) concentration ratio of the ammonia-alkaline solution, in which TeO<sub>2</sub> solubility is higher than that in acidic solution.
- Jitsumu Hyomen Gijutsu
Jitsumu Hyomen Gijutsu 48(7), 728-732, 1997-07-01
The Surface Finishing Society of Japan