Effect of electrolyte on the growth of thermoelectric Bi2Se3 thin films

Bismuth Selenide (Bi2Se3) is a thermoelectrical material showing high Seebeck coefficient and figure of merit. It can be obtained by electrodeposition which makes it highly suitable for application in sensor and thermoelectric generators. Here, electrodeposition of Bi2Se3 on silicon(100) substrate was studied using different deposition baths by changing the salts and acid concentrations. The thin films were characterized to obtain the morphology, structural and thermoelectric properties. An optimal bath was found that leads to crystalline thin films with compact and uniform morphology, showing high values of Seebeck coefficient. The total salt concentration directly changes the structural properties of the samples, while the relative salt concentration essentially modifies the stoichiometry of deposits. The acid concentration, otherwise, promotes changes in the grain size and morphology.