Optical Properties of Ternary Alloyed CdSe $$_{1-x}$$ 1 - x Te $$_x$$ x Quantum Dots

Raman, absorption and photoluminescence (PL) spectra of ternary alloyed CdSe $$_{1-x}$$ Te $$_x$$ quantum dots (QDs) with various values of x have been studied at room temperature. The average diameter of QDs is about 5.1 nm. The actual chemical composition was estimated by Raman spectroscopy. The values of 1.13 ± 0.06 eV and 1.01 ± 0.03 eV for the band gap bowing coefficient were obtained by fitting the composition dependence of the band gap and the PL peak energy, respectively, to the nonlinear Vegard formula. The PL quantum yields (QYs) were in the range of 24–53%. The relationship between PL peak wavelengths and quantum yields was investigated. It is shown that the QY dependence on the composition is associated with the crystalline quality of the alloy.