## 3 Results and Discussion
### Band Gap Energy and Resistance of Electrodeposited Zinc Telluride  
Figure 5a shows the post-annealing effect on the UV-VIS absorption spectra of zinc telluride thin films. In the zinc telluride thin film annealed at 653 K, light absorption was confirmed in the spectrum region less than 735 nm. By contrast, the zinc telluride thin film with annealing at 683 K exhibited light absorption in the spectrum region less than 535 nm. [PERSON] et al. investigated the UV-VIS absorption performance of zinc telluride  
Figure 4: Effect of the annealing temperature on the X-ray diffraction profiles of electrodeposited ZnTe thin films onto ITO glass substrates. The as-deposited sample (**a**) was annealed for 5 h at 653 K (**b**), 663 K (**c**), 673 K (**d**), and 683 K (**e**). Cu-K\(\alpha\) radiation was used as the X-ray source (40 kV; 30 mA) and the scan rate of the goniometer was set to 5 degrees per minute. nanowire samples that were electrochemically synthesized into TiO\({}_{2}\) nanochannels [32]. They reported observing light absorption in the spectrum region less than 688 nm using as-electrodeposited zinc telluride nanowires, whereas zinc telluride nanowires annealed at 623 K exhibited a light absorption performance in the spectrum region less than 559 nm. The authors concluded that the post-annealing treatment resulted in the elimination of crystal defects, such as zinc vacancies, which existed in the as-electrodeposited zinc telluride nanowires. Hence, in the present study, the wavelength shift in the optical absorption seemed to have been induced by the crystallization of the as-deposited zinc telluride amorphous-like phase during the thermal annealing process. Figure 5b shows the post-annealing effect on the \((\Delta hv)^{2}\) versus the \(hv\) plot that determines the band gap energy \(E_{\text{g}}\) of zinc telluride films. The electrodeposited zinc telluride samples were annealed at 653 K and 683 K. The \(E_{\text{g}}\) of zinc telluride films with annealing at 653 K and 683 K were determined to be approximately 1.7 eV and 2.3 eV, respectively. [PERSON] et al. also reported that the \(E_{\text{g}}\) of single-phase zinc telluride, which was electrodeposited from an EMIC (1-ethyl-3-methylimidazolium chloride) solvent, was approximately 2.3 eV [30]. Hence, the \(E_{\text{g}}\) observed in our study agrees well with their results. Figure 6a shows the post-annealing effect on the \(E_{\text{g}}\) of zinc telluride films. The \(E_{\text{g}}\) of zinc telluride films annealed at 653-673 K was estimated to be approximately 1.7 eV, while that of the zinc telluride film annealed at 683 K was determined to be approximately 2.3 eV, which was almost identical to that of the single-crystal zinc telluride. The electrodeposited thin films annealed at 653-673 K were composed of binary phases (ZnTe and Te), whereas the thin film with annealing at 683 K consisted of single-phase zinc telluride, as shown in Figure 4. Therefore, the band gap energy of electrodeposited zinc telluride thin films seemed to depend on the constituent phase. The tellurium phase in the electrodeposited thin films should decrease the energy band gap. Figure 6b shows the post-annealing effect on the resistivity of zinc telluride thin films. The resistivity of the as-prepared zinc telluride thin film was approximately 2 \(\times\) 10\({}^{5}\)\(\Omega\cdot\)m, whereas that of the zinc telluride thin films annealed at 653-683 K was approximately 2 \(\times\) 10\({}^{3}\)\(\Omega\cdot\)m, which was smaller than that of single-crystal zinc telluride. [PERSON] et al. revealed that the resistivity of electrochemically synthesized zinc telluride thin films was strongly affected by the post-annealing process [23]. Based on their report, the sheet resistance of the zinc telluride thin film annealed at 623 K was approximately 0.3 \(\times\) 10\({}^{5}\)\(\Omega\)/sq., while that of the films annealed at 648 K and 673 K were approximately 1.1 \(\times\) 10\({}^{5}\)\(\Omega\)/sq. and 8.2 \(\times\) 10\({}^{5}\)\(\Omega\)/sq, respectively.