Raman scattering and electrical conductivity of nitrogen implanted MoO3 whiskers

Whiskers of MoO3 have been grown by a thermal transport process. A set of samples was then implanted with nitrogen ions at a dose of 5 × 1016 ion/cm2. The implanted whiskers changed from transparent to semi-transparent. Raman spectroscopy of the whiskers was observed and compared with those of unimplanted whiskers. The results revealed that the Raman intensity of the implanted whiskers was decreased about 10 times with respect to that of unimplanted whiskers. Only the case of the wave propagation parallel to the a-axis, a lower suppression ratio of the B3g modes was observed. No extra mode due to the nitrogen implantation was observed. This indicates that implantation could only induce defects and oxygen vacancies but not the structural transformation. From electrical conductivity and Hall measurement, it was found that the whiskers exhibited an n-type semiconductor and its conductivity drastically increased due to the defects and oxygen vacancies.