There is an increasing interest in semiconductor/ electrolyte systems in connection with their application as phototelectrolytic energy conversion devices (e.g. hydrogen evolution). There are several requirements in order to produce hydrogen by photoelectrolysis using oxides metals and semiconductors. For example, the distance between the conduction band and the Fermi level of the semiconductor must be larger than the redox potential of water. Therefore, water has an effective redox potential of 1.3-1.4 eV. The semiconductor must have a band gap of at least 1.7 to split water.
One of the most interesting semiconductor materials is the CuGaSe2. This material offers a direct band gap with a value of 1.68 eV, and it is a good prospect for splitting of water. There are different types of methods to prepare it, for example by chemical vapor transport (CVT)and also by physical vapor deposition (PVD). However, by electrodeposition technique still not reported.
In this paper shows the Cu-Ga-Se precursors are prepared via electrodeposition, using a plating bath of CuCl2, GaCl3, H2SeO3, and Sodium Citrate as a complexes agent, using different molar ratio. A standard three-electrode cell was used to prepare it. The precursor films were made under Galvan static conditions, at different time of deposition. The average thickness of the samples was approximate to 1.5 μm. After electrodeposition precursor thin films were annealed in a Nitrogen atmosphere with Selenium shots during 30 min. The annealed films were characterized by electrochemical; photoelectrochemical, compositional, and morphologic methods in order to know its potential for water splitting.