Group III–V and II–VI Quantum Dots and Nanoparticles

Abstract

By decreasing the size of semiconducting material the novel properties appear from the increased surface/bulk ratio and quantum confinement effects. X-ray absorption spectroscopy (XAS) can be applied to quantum dots and nanoparticles in-situ in the colloid, on the substrate or inside a solid matrix. The structural information about average size, phase composition, and growth orientation can be extracted from XAS along with information about electronic and magnetic properties of pure and doped nanostructures. In the chapter we shall describe the general properties of quantum dots and their applications that will help to understand the tasks for spectroscopy. Case studies will provide the information that is obtained from XAS complementary to other methods. Properties and Applications of Quantum DotsNanoparticle (NP) and quantum dot (QD) are regarded as zero-dimensional nanostructures. The term "QD" is usually used for semiconductor nanoparticles and islands where quantum confinement of electrons and excitons determines their properties. Decades passed after the dependence of the spectral position of the exciton absorption lines of the nanosized CuCl crystals was attributed to the quantum size effect [1] and three-dimensionally confined semiconductor quantum wells or zero-dimensional semiconductor nanostructures showing discrete electronic states were named "QDs"

X-Ray Absorption Spectroscopy Study of Battery Materials

“…The second consideration concerns the EXAFS data analysis of nanoparticles and nanostructures [41,42]. This issue has been addressed for metal nanoparticles first [43], evidencing that by decreasing the size of the material there is a significant effect on the observed coordination number, due to the increased surface/bulk ratio.…”