Electrodeposition of Zinc Telluride Thin Films for Photovoltaic Applications

This work studies the electrodeposition of Zinc Telluride (ZnTe) thin films. ZnTe is a p-type semiconducting material that shows potential for incorporation in solar devices due to its band gap energy of 2.26 eV. The deposition of ZnTe has been studied before; as such, the objective of this work was to first confirm and replicate these results. From there, we aimed to further understand its synthesis, with the overall goal of depositing smooth layers onto an indium-tin-oxide substrate. We performed the electrodeposition of multiple ZnTe films at 90 °C in a solution of 0.15 M Zn(NO₃)₂ and 0.5 mM TeO₂ at a pH of 3.5. The deposition was run for 30 minutes at a potential of -1.1 V. Analysis of the deposited films was performed by using a scanning electron microscope to assess the smoothness and atomic structure, and by using a spectrometer to obtain optical properties of the films. The films produced exhibited band gap energies ranging from 1.95 eV to 2.25 eV. These values indicate that some of the films had been successfully electrodeposited to expected criteria. In continuing this work, we plan on using more analytic methods to assess the films, such as atomic force microscopy to more accurately determine film smoothness and energy dispersive spectroscopy to obtain film composition. Once we can confirm the films are being deposited to our specifications, we plan to deposit ZnTe into layered ZnTe/ZnO nano-rod structures for use in solar photovoltaic applications.