FORMATION AND LATTICE DISTORTION OF NANOCRYSTALLINE SELENIUM

A nanocrystalline selenium (nc-Se) was prepared by completely crystall izing the as-quenched amorphous selenium. The structure of the nc-Se w as investigated by x-ray diffraction (XRD) and transmission electron m icroscopy (TEM). The nc-Se with trigonal structure consists of lamella e which are composed of whiskers with a nanometer-sized thickness. It was found that the lattice parameter a increase, but c decreases simul taneously with a reduction of grain size. When the grain size is small er than 12 nm, the crystal lattice is found to be expanded; whereas fo r the grains larger than 12 nm, the crystal lattice is contracted.