Growth and optical band gap of CdAl-layered double hydroxide thin structures on rigid substrate

We report the optical and chemical properties of a CdAl-layered double hydroxide (LDH) grown by a low-temperature hydrothermal method on rigid substrates. Structural and chemical investigations showed that the CdAl-LDH structures were formed as the source concentration was increased up to 45 mM. Mixed phases of CdO, Cd(OH)2, and CdAl-LDH structures were formed when the source concentration was less than 30 mM. X-ray photoelectron spectroscopy indicated that the Cd and Al metal ions were present in the LDHs as divalent and trivalent ionic states, respectively. Optical investigations by UV-vis spectroscopy indicated that the CdAl-LDH had a direct band gap structure with an energy band gap of 3.01 eV.