The results of laser selective excitation indicate that the emission centers near the surface exhibit inhomogenously br oadened spectra while the two different symmetry sites inside the nanotube - walls present legible spectral structures . silicon nanowires were prepared by a thermal evaporation method 受表面缺陷的影响,纳米管壁近表面的eu ~ ( 3 + )离子处于较为复杂的微环境中,其发射光谱表现为非均匀展宽的光谱线形。