Electrodeposition of HgCdTe thin films

HgxCd1−xTe thin films in the compositional range x=0.05–0.6 were grown on SnO2-coated glass substrates using the electrodeposition technique. The electrochemical bath consisted of aqueous solutions of CdCl2, HgCl2 and Te reacted with HNO3, along with a complexing agent CH3CN (acetonitrile). The conditions for the growth of HgCdTe from such a bath were ascertained with the help of cyclic voltammetry (CV) curves. Studies indicate that single-phase HgCdTe can be electrodeposited from the bath only if it is thoroughly mixed over a period of time, prior to the deposition. The films were characterized by X-ray diffraction (XRD), scanning electron microscopy and electron microprobe studies. XRD data show that single-phase material was obtained over the whole range of compositions studied. The films were polycrystalline having the cubic fcc structure and the (1 1 1) orientation. The best stoichiometry HgCdTe films grown from the baths of composition X=0.15, 0.3 and 0.6 were obtained at deposition potentials 0.65, 0.7 and 0.75 V (versus saturated calomel electrode (SCE)) respectively, the corresponding film compositions being x=0.16, 0.4 and 0.6, respectively.