Eq.2 I110 is the maximum intensity of the crystalline peak from the (110) lattice diffraction, and Iam is the intensity of amorphous diffraction at 2θ = 10.4°. The transmission electron microscope (TEM) images, HR-TEM images, STEM images, and energy-dispersive X-ray (EDX) analysis/mapping were captured using JSM-2100 (JEOL, Japan). FT-IR spectra were taken using a Nicolet model 6700 spectrophotometer (Thermo Fisher, USA). X-ray photoelectron spectroscopy (XPS) spectra of CdS/CTS and Cu-CdS/CTS were recorded using a Thermo Fisher (K-alpha, Al Kα radiation).