Optical, morphological and thermal investigation of Cu doped ternary semiconducting (Cd1-xZnxS:Cu) nanomaterials

Abstract Cd1-xZnxS:Cu (x ≤ 1) nanomaterials have been synthesized successfully using chemical co− precipitation method. The EDX spectrum shows successful doping of Cu in the lattice of CdZnS alloy. Two and three dimensional surface morphology is imaged by AFM technique. RMS roughness observed at 33.5 nm and roughness height measured around 200 nm. The UV–visible spectra have absorption at 278, 244, 242, 231, 221 and 220 nm with Zn (x = 0, 0.1, 0.3, 0.5, 0.7, 0.9) respectively. This shows a blue shift in the absorption spectra due to quantum confinement effect. The band gap is determined in the range 3.75–5.44 eV with Zn concentration (x = 0 to 0.9).Quantum dots formation is confirmed by UV–visible analysis. The photoluminescence investigation reveals broad and asymmetric emission in the orange-red region at 600 nm wavelength which may be due to the recombination of Cu2+ related defect states.TGA/DTA investigation, indicated that ternary Cd0.1Zn0.9S:Cu(0.01M) type semiconductor QDs are prepared more stable structures with high crystallinity as compared to binary CdS:Cu(0.01M),supported by our earlier published XRD results. Two luminescence peaks appear with a small frequency difference related to intrinsic luminescence and Cu induced defect states in the band gap. Thermal properties indicate almost thermally stable nanomaterials may be useful for LED and semiconductor laser.