Cathodoluminescence defect characterization of hydrothermally grown SnO2 nanoparticles

SnO(2) nanoparticles in the 50 - 150 nm size range were grown by a low temperature hydrothermal process, using SnCl(4) center dot 5H(2)O as precursor and CH(3) ( CH(2) ) (15)N ( Br ) ( CH(3))(3) as stabilizing agent. The as- grown samples were mostly amorphous and their crystallinity improved either by prolonged hydrothermal process or by air annealing at high temperatures. The absence of near- band- edge emission and appearance of a broad visible emission related mainly to oxygen vacancies and crystalline defects were the main characteristics of their room temperature cathodoluminescence ( CL ) spectra. A luminescent band in the 1.79 - 1.83 eV spectral region was also detected. The intensity of the defect bands reduces both on prolonged hydrothermal treatment and air annealing at high temperatures, indicating a net decrease of defect content on thermal treatments. Panchromatic CL images revealed that most of the defect emissions come from smaller SnO(2) nanoparticles. (C) 2008 American Institute of Physics.