Observation of phonon modes in PbTe nanocubes prepared by a solvothermal route

A facile solvothermal route to grow PbTe nanocubes is demonstrated. A rational growth mechanism for the formation of PbTe nanocubes was proposed. Phonon modes of the as-prepared PbTe nanocubes have been studied by Raman scattering. Raman scattering results indicated that strong TeO₂ phonon vibrational modes were detected on the surface of as-synthesised PbTe nanocubes. These strong TeO₂ phonon vibrational modes obscured the observation of the longitudinal optical (LO) phonons of PbTe in early conventional Raman scattering experiments. After removal of TeO₂ layers by chemical etching, the LO phonons that are Raman inactive vibrational modes for PbTe were obviously observed in PbTe nanocubes.