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LUMINESENCE AND CONDUCTIVITY STUDIES OF MAGNESIUM OXIDE NANO PARTICLES

Sharmila P P

Nanoparticles of magnesium oxide (MgO) have been prepared simple chemical precipation followed by calcination. Powder X-ray diffraction (PXRD) patterns of MgO samples  show cubic structure. The Scanning Electron Microscopy (SEM) studies reveal formation of highly porous, foamy and flake like structures. The optical absorption studies of MgO show surface defects in the range 250–300 nm. The absorption peak at ∼250 nm might be due to F-centre. Photoluminescence (PL) studies were carried upon exciting at 250 nm. There are two peaks in the spectrum of all the synthesized samples, one between 320-350nm and another between 410-450 nm. The emission in the 320 range is sharp but the other peak is very broad. This emission can be attributed to the displacement of oxygen ions and subsequent electron trapping resulting in the formation of F centres. These emission peaks were due to surface defects present in the sample since nanoparticles exhibits large surface to volume ratio and quantum confinement effect.