Formation and lattice distortion of nanocrystalline selenium

Abstract

A nanocrystalline selenium (nc-Se) was prepared by completely crystallizing the as-quenched amorphous selenium. The structure of the nc-Se was investigated by x-ray diffraction (XRD) and transmission electron microscopy (TEM). The nc-Se with trigonal structure consists of lamellae which are composed of whiskers with a nanometer-sized thickness. It was found that the lattice parameter a increases, but c decreases simultaneously with a reduction of grain size. When the grain size is smaller than 12 nm, the crystal lattice is found to be expanded; whereas for the grains larger than 12 nm, the crystal lattice is contracted.