Photoluminescence and electroluminescence properties of Cu-doped ZnS thin films fabricated by ultrasonic spray pyrolysis
Angélica Carrillo Verduzco, Jesús Uriel Balderas Aguilar, J. C. Alonso
Abstract
Herein, we report the development of a simple and cost-effective ultrasonic spray pyrolysis (USP) technique for the deposition of ZnS thin films doped with various Cu atomic concentrations in the starting solution (ZnS:Cu(x%), with x = 1, 2.5, 5, 10 and 15) without the need for further annealing. This approach was employed to integrate the doped thin films as the active layer in an AC-driven electroluminescent device, allowing for a complete MISIM multilayer structure fabricated solely by USP. The X-ray diffraction (XRD) study showed that the Cu-doped ZnS thin films are polycrystalline and highly oriented along the (002) direction. Their energy band gaps were in the range of (3.46 eV – 3.53 eV) according to diffuse reflectance spectroscopy (DRS). A lamella was extracted from the MISIM structure with 15 % Cu content using focused ion beam (FIB) slicing. The scanning-transmission electron microscopy (STEM) revealed that the device has an approximate thickness of 650 nm. Differences between the electroluminescent and photoluminescent emissions are discussed. • Electroluminescent device with bluish-white emission. • Difference between photoluminescence and electroluminescence. • Device fabricated by a low-cost spray pyrolysis deposition method.