Temporal control of CdSe layering on ZnSe by chemical bath deposition technique

This study investigates the novel temporal control of CdSe deposition on ZnSe thin films using chemical bath deposition technique to fabricate ZnSe/CdSe heterostructures. Pristine ZnSe and CdSe films were deposited for 2 h each, while heterostructures were synthesized by varying CdSe deposition times from 15 to 120 min on ZnSe layers. The structural, morphological, and optical properties of the films were systematically investigated as a function of CdSe deposition time. X-ray diffraction confirmed the formation of hexagonal wurtzite phase, with the (002) plane emerging as the preferential orientation. Increasing CdSe deposition time improved crystallinity and promoted lattice strain relaxation. Field emission scanning electron microscopy revealed a morphological transition from sheet-like ZnSe to rod- and maggot-like CdSe/ZnSe composites, consistent with nucleation-driven growth. Energy-dispersive X-ray spectroscopy confirmed the expected elemental composition, while Raman spectra showed characteristic vibrational modes of both CdSe and ZnSe. Fourier-transform infrared spectra analysis further supported the formation of chemical bonds within the films. Optical measurements revealed a tunable band gap ranging from 2.75 eV to 1.64 eV with increasing CdSe deposition time. Photoluminescence spectra indicated near-band-edge and defect-related emissions, including an enhanced green emission attributed to ZnSe/CdSe interfacial states. These findings demonstrate that CBD-grown ZnSe/CdSe heterostructures exhibit tunable optical properties suitable for optoelectronic and luminescent device applications.