Optical properties of single-crystalline alpha-Si3N4 nanobelts

The optical properties of single-crystalline alpha-Si3N4 nanobelts synthesized via catalyst-assisted pyrolysis of polymeric precursor were characterized by absorption, photolurninescence (PL) and photoluminescence excitation (PLE). The optical absorption spectrum showed that the nanobelts exhibited indirect absorption behavior with optical band gap of similar to5.0 eV. Three broad peaks centered at 1.8, 2.3, and 3.0 eV were observed from the room-temperature PL spectrum of the nanobelts. The PLE spectra suggested the existence of multifold energy levels within the gap. A qualitative model was proposed to explain the observed absorption, PL and PLE spectra. (C) 2005 American Institute of Physics.