Thermodynamics of cathodic ZnTe electrodeposition using basic ammoniacal electrolytes: Why CdTe can deposit while ZnTe cannot

Abstract

Potentiostatic cathodic electrodeposition of ZnTe compound was attempted using ammoniacal basic electrolytes in which Zn(II) and Te(IV) species were dissolved to form Zn(NH 3) 2+4 and TeO 2-3 ions. The ZnTe electrodeposition ended unsuccessfully although CdTe can electrodeposit from similar ammoniacal solutions under a variety of conditions. The solubility of Te(IV) species and cathodic polarization behaviors indicated the absence of interionic interaction between Zn(II) and Te(IV) ions unlike the case between Cd(II) and Te(IV). A potential-pH diagram of the Zn-Te-NH 3-H 2O system constructed based on diagrams of the Zn-NH 3-H 2O and Te-H 2O systems also demonstrated several thermodynamic and/or kinetic factors that make ZnTe deposition more difficult than those of CdTe. Copyright © 2011 De Gruyter.