ANALYSIS OF LOCAL ATOMIC STRUCTURE OF QUANTUM DOTS OF CdS FAMILY
A. N. Kravtsova, I. A. Pankin, M. A. Soldatov, V. V. Butova, I. A. Bobrova, A. V. Soldatov
IRC "Smart materials", Rostov-on-Don, Russia
Keywords: квантовые точки, сульфид кадмия, спектроскопия XANES высокого разрешения, атомная структура, компьютерное моделирование, quantum dots, cadmium sulfide, high energy resolution XANES spectroscopy, atomic structure, computer modelling
Abstract
The microwave synthesis of quantum dots based on CdS has been performed, the temperature ( T 180°C and 150°C) and synthesis duration (10 min and 5 min) have been varied. The analysis of the peak broadening in X-ray diffraction has shown that the average particle size in the synthesized samples is 10.02 nm for the CdS T = 180°C sample and 5.22 nm for the CdS T = 150°C sample. For both synthesis temperatures particles of sphalerite phase are formed but the sample CdS T = 180°C contained some impurity of wurtzite phase too. Cd K -XANES spectra in the standard samples and quantum dots have been recorded using a Rigaku R-XAS X-ray absorption laboratory spectrometer. The theoretical analysis of the Cd K -XANES spectra of bulk samples of CdS and CdS nanoparticles has been performed. It has been shown that the theoretical difference spectra between bulk CdS and CdS with decreased lattice parameters demonstrate the same tendency as the experimental difference spectra between bulk CdS and the quantum dot samples under study. It has been shown that the theoretical Cd K -edge HERFD-XANES spectrum in CdS demonstrates considerably more detailed structure pointed to the need of the analysis of experimental Cd K -edge HERFD-XANES spectra to pick out more precise information on local atomic structure parameters of small semiconducting quantum dots.
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