Optical properties of ternary alloyed Zn_xCd_1-xSe semiconductor nanocrystals

In this study, ternary alloyed Zn_xCd_1-xSe (x=0, 0.2, 0.5, 0.8 and 1) semiconductor nanocrystals with high quality are synthesized by a high temperature decomposition route. The effect of Zn content (x) of Zn _xCd_1-xSe semiconductor nanocrystals on their physical properties is investigated by controlling the Zn/Cd ratios. The optical properties and morphologies of the prepared nanocrystals are measured by FL, UV-Vis and TEM techniques. The actual composition of the prepared nanocrystals based on the ICP results is Zn_0.03Cd_0.97Se, Zn _0.12Cd_0.88Se, and Zn_0.38Cd_0.62Se when Zn content is 0.2, 0.5, and 0.8, respectively. The fluorescence properties of the obtained alloyed Zn_xCd_1-xSe nanocrystals posses pure green light color and narrow particle size distribution (FWHM=28-30 nm). It is found that the emission wavelength of nanocrystals shifts from 510 to 545 nm with increasing Zn content from 0 to 0.8, although based on the TEM measurements, the particle sizes of Zn_xCd_1-xSe nanocrystal for different Zn content (0-0.8) are almost about 3.2 nm. Therefore, the wavelength shift and nonlinear optical property of the Zn_xCd _1-xSe nanocrystals is not caused by the particle size but the compositional effect..