Influence of precursor pH on Bi doped ZnSe material via electrochemical deposition technique

Bismuth zinc selenide (Bi:ZnSe) thin film was synthesized using electrochemical deposition technique. An aqueous solution of 0.15 mol of ZnSO4•7H2O served as the cationic precursor while the anionic precursor was 0.1 mol solution of selenium metal powder dissolved in 5 ml of hydrochloric acid (HCl) to ensure uniform deposition. The precursor pH was varied at 8, 8.5 and 9. The X-ray diffraction peaks of Bi:ZnSe thin films at different pH were obtained at (220), (221), (300), (310), (311), (222) and (320). The optical band gap energy of Bi:ZnSe thin films grown at pH of 8, 8.5 and 9 decrease from 2.3 – 1.9 eV. The refractive index of Bi:ZnSe grown at pH of 8 and 8.5 exhibited the same thread whereas that of pH of 9 has the highest refractive index.