Characterisation of electroplated Bi-2(Te1-xSex)(3) alloys

Composition modulated Bi-2(Te1-xSex)(3) thin films were prepared on stainless steel substrates by cathodic electrodeposition. The composition was dependent on the deposition conditions. It was possible to obtain, in the same electrolyte, films with either an excess or a deficiency of bismuth in relation to stoichiometric Bi-2(Te0.9Se0.1)(3) by changing the deposition potential or the applied current density. The excess of bismuth was reached at the highest cathodic conditions. The variation of the crystallographic axis and the morphology with a granular structure were correlated with the presence of the Bi enrichment in the ternary. The crystallographic texture of bismuth telluride films was studied according to the electrodeposition conditions. The films presented a fibre texture, and a main orientation {11.0} was observed. Electrical and thermoelectric properties of a Bi1.98Te2.67Se0.39 film were measured and showed an n-type behaviour.