Optical Properties of Ternary Alloyed ZnxCd1-xSe Semiconductor Nanocrystals

In this study, ternary alloyed ZnxCd1-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 ZnxCd1-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 Zn0.03Cd0.97Se, Zn0.12Cd0.88Se, and Zn0.38Cd0.62Se when Zn content is 0.2, 0.5, and 0.8, respectively. The fluorescence properties of the obtained alloyed ZnxCd1-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 ZnxCd1-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 ZnxCd1-xSe nanocrystals is not caused by the particle size but the compositional effect.