Effect of Magnesium Doping on the Optical and Electrical Properties of Cd- Se Quantum Dots

Present study reports that Cd-Se nanoparticles with zinc blende structure allow Magnesium (Mg) Doping. Size tunable pure Cd-Se and Mg doped Cd-Se nanocrystal quantum dots were synthesized by inverse micelles technique. Paraffin oil and oleic acid were used as a solvent and surfactant respectively. Reduction in particles size with increase in Mg content is estimated from X-ray diffraction (XRD) peaks and some theoretical formulations. UV-Vis absorption spectra (300-900 nm) show a clear cut size dependent blue shift with the addition of Mg content, as a result of quantum confinement effect. The optical band gap, calculated using Tauc’s plot, increases with increase in Mg doping in Cd-Se lattice. Temperature dependent electrical conductivity reveals that the dark conductivity and charge carrier concentration decreases with the addition in Mg content. The dark activation energy is calculated using Arrhenius plots. A good agreement is seen in experimentally calculated optical band gap and dark activation energy. Both are found to increase with increase in Mg content. The results show that doping of Mg significantly influence the particle size, optical band gap, activation energy and conductivity in Cd-Se quantum dots. Tailoring of optical and electrical properties in effective way, with Mg doping, control their light emission colours and maybe useful for opto-electronic devices.