Nd-doped CdS nano-particles: optical band gap and Urbach energy investigations

CdS:Nd³⁺ nano-particles were synthesized by chemical precipitation method and characterized by EDAX, XRD and absorption spectra and SEM imageries. XRD spectra were recorded in terms of 2θ versus counts. The particle sizes were calculated by using the strongest diffraction peak with Debye-Scherer formula. From the XRD analysis, the average particle size of CdS:Nd³⁺ nano-particles were found to be 1 to 50 nm. The absorption spectra, consisting of several absorption bands, have been recorded for 400–900 nm wavelength. From the absorption edge, the optical band gap and Urbach energy were computed. The concentration of Nd³⁺ ion increases as the optical band gap and Urbach energy decreases. The presence of the high intensity peaks shows that the prepared sample were highly crystalline in nature. The obtained range of band gap is suitable for optoelectronics applications like solar cell fabrication and high frequency application.