On the Optical, Thermal, and Vibrational Properties of Nano-ZnO:Mn, A Diluted Magnetic Semiconductor

Nano-zinc oxide and Mn-doped zinc oxide were synthesized by a chemical process, and the average size of the particles observed was 35 nm for nano- ZnO. Optical and thermal characterizations were carried out by means of photoluminescence and photoacoustic spectroscopy. It was found that nano- ZnO has a thermal diffusivity one order of magnitude larger than bulk ZnO. Similarly, a less explored localized defect mode in ZnO:Mn was studied theoretically and experimentally using FTIR spectroscopy. The localized mode was experimentally found to be 514 cm−1, compared to its theoretical value of 502 cm−1. These values suggest that the current theory of bulk materials can also be extended to nanosystems and they are consistent with our hypothesis that Mn goes substitutionally as an impurity displacing Zn in nano-ZnO.