Synthesis of ZnSe nanocrystalline powders by mechanochemical reaction

The ZnSe nanocrystalline powders were synthesized by mechanochemical reaction method. The powders milled at air atmosphere have the second phase ZnO, but that milled above 2 h at high N-2 atmosphere have not second phase ZnO. The phase structure of the ZnSe powder milled for 10 h at N-2 atmosphere is sphalerite structure. The average size of the as-milled and annealed ZnSe nanocrystalline powders is 5.17 and 8.88 nm respectively. The TEM analysis demonstrated that the size of agglomerated ZnSe crystalline is less than 100 nm, but the electron diffraction pattern showed that ZnSe clusters were a polycrystalline structure. The absorption spectrum of ZnSe samples was measured by UV-VIS-NIR Photometer Spectrum. It showed that the absorption edge of the ZnSe nanocrystalline powders by mechanochemical reaction comparing to ZnSe bulk materials had a red-shift. This result can be attributed to the residual stress and lattice aberrance of ZnSe nanocrystalline powders in milling process. The absorption edge of the annealed ZnSe powders was recovered owing to the residual stress was eliminated by annealing for 2 h containing nitrogen.