International Journal of Science and Technology (IJST)

Electro-Optical Characterization and Enhanced Electroluminescence of Copper-Doped CdTe and ZnTe Quantum Dot for Nano-LED Applications

This study presents electro-optical characterization of self-assembled thin films composed of copper-doped CdTe and ZnTe quantum dots synthesized via a straightforward chemical route. High-resolution transmission electron microscopy (HRTEM) confirm that the CdTe:Cu and ZnTe:Cu quantum dots adopt a spherical structure with sizes below 15 nm and can be uniformly incorporated into thin films. Scanning electron microscopy (SEM) reveals surface morphology and roughness of these films. Optical absorption measurements show a blue-shifted sharp absorption edge at 426 nm for CdTe:Cu, corresponding to an increased band gap energy of 1.23 eV. For ZnTe:Cu quantum dots, a band gap increase of 1.91 eV is observed. Electroluminescence (EL) spectra of CdTe:Cu closely match their fluorescence spectra, exhibiting smooth and sharp emission peaks between 605 and 614 nm. Also ZnTe:Cu quantum dots demonstrate intense green luminescence, attributed to effective Cu²⁺ ion incorporation, which enhances emission intensity in both nanocomposites. These findings highlight that copper doping significantly modifies the optical properties of CdTe and ZnTe quantum dots, producing enhanced luminescence suitable for applications in nano light-emitting devices (nano-LEDs). The ability to chemically prepare homogeneous films with controlled optical features offers promising opportunities in optoelectronic device fabrication.