Preparation and characterization of pure phase CdMnTe nanopowders by a hydrothermal route.

In this paper, CdMnTe nanopowders with uniform shapes were prepared through a facile hydrothermal route using 3-mercaptopropionic acid (MPA) as the stabilizer and modifier. The effects of different experimental conditions including Cd-to-MPA ratio, pH value and reaction temperature on the phase composition and formation mechanism of as-prepared nanopowders were studied. XRD results indicated as-prepared CdMnTe nanopowders were pure phase and had cubic sphalerite structure with high crystallinity. SEM and Rietveld refinement clearly showed that the powders were about 10-100 nm in size. In PL measurement, there was a strong luminescence peak in the infrared region 1.717-1.826 eV. Compared with the CdMnTe single crystal, a blue shift of about 0.109 eV indicated a wider band gap. In UV-vis spectra, the absorption peak of the sample blue shifted with the decrease of crystal size, which indicated an obvious quantum confinement effect (QCE) in nanopowders. The optimal conditions for the preparation of CdMnTe nanopowders are 180 °C for 24 h with the molar ratio 1 : 1 of Cd : MPA at pH 13. In particular, the growth kinetics and possible formation mechanism of the nanopowders were proposed.