Sn-doped ZnO nanocrystals were synthesized by the hydrothermal method using ZnCl

2

and NaOH as raw materials at 200℃ for 5 h. The dopant source of tin was SnCl

4

·4H

2

O and the atomic percentage of dopant in the solution were

n

(Sn):

n

(Zn) = 1% and 2% respectively. The phase composition

morphology

size as well as optical properties of the samples have been characterized by means of X-ray diffraction (XRD)

field emission scanning electron microscopy (FE-SEM)

UV-Visible absorption and photoluminescence (PL) spectra. The effects of the Sn doping concentration and the pH value of the precursor solution on the surface morphology and optical properties of the samples have also been studied. The experimental results indicate that the obtained Sn-doped ZnO nanocrystals are of hexagonal wurtzite structure. The average grain size of the samples increases and the surface morphology goes from short rod-like to single cone-like and double cone-like with the increase of Sn concentration. In addition

the surface morphology of the samples can also be affected by the basicity of the precursor solution. Since it changes from long rod-like (for pH 7.0) to short rod-like (for pH 12.0). There was a UV absorption peak from the UV-visible absorption spectra which have a red-shift with the increase of Sn concentration. Three photoluminescence bands

including a strong purple emission at 433 nm

a left-shoulder near UV band emission around 401 nm as well as a weak blue emission at 466 nm were observed at room temperature. The intensities of the emission peaks increased with the increase of Sn concentration. Compared with that of undoped ZnO nanocrystal

only the intensities of emission peaks are changed

but the peak positions are almost not changed in the Sn doping concentration rang of our experiments.