Enhanced photoelectrochemistry properties of CdZnTeSe thin films

CdZnTe (CZT), as an optimum absorption layer, has many attractive characteristics for photoelectrochemical (PEC) water splitting, such as tunable band gaps (1.45-2.26 eV) and high absorption coefficient (>= 104 cm- 1). The addition of Se into CZT was found to be very effective in arresting the formation of sub-grain boundaries, improving compositional homogeneity. In this paper, CZT films were deposited on fluorine-doped tin oxidecoated (FTO) substrates by close-spaced sublimation method. The influence of selenization process to the structural, morphological, and optical properties of CZT films was studied. The phase purity properties of CdZnTeSe (CZTS) films were analyzed by X-ray diffraction (XRD), energy disperse spectroscopy (EDS) and Raman spectra measurements. The morphological characteristics of CZTS films were characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The PEC properties of CZTS films were also investigated, which indicated that the photocurrents of CZTS films were greatly increased than that of asdeposited CZT films. The mechanism of PEC enhancement of CZTS films were studied detailedly.