Surfaces of Cd(S, Se) Nanoparticles by Small-Angle X-ray Scattering

A dilute system of CdS_xSe_{1 - x} nanocrystals has been studied by means of small-angle X-ray scattering. Information about the surface state has been obtained, taking advantage of the large-q part of the scattering curve. The presence of edges at the surface of the nanoparticles is evidenced by the limit at zero of the chord-distribution function. On the other hand, the information obtained from the high-q part of the scattering curve is compared to that deduced from the whole spectrum. This comparison shows that a polyhedral model is needed to account for the surface of the scattering particles. The particle-size distribution, evaluated assuming edged particles, is in good agreement with the expected distribution and yields a satisfactory simulated spectrum. Some properties of the particle structure can be suggested from the presence of the edges.