掺铒纳米硅的选择激发光荧光研究

通过选择激发光荧光技术研究了生长在SiO2中的掺铒纳米硅（nc—Si：Er）的光学性质。当激发光光子能量高于1．519eV时，nc—Si：Er的室温光荧光谱上能够看到两个清晰的发光峰，一个来自nc—Si，峰值位置在1．39eV，标记为Enc-Si；另一个发光来自nc—Si附近的Er离子，峰值位置在0．81eV，标记为EEr,当激发光的光子能量为1．42eV时，尽管该能量高于Enc-Si和EEr的峰值能量，在nc—Si：Er的室温光荧光谱上既看不到Enc-Si的发光蜂，也看不到EEr的发光峰。研究发现，当激发光光子能量与Er离子的一些激发态能量共振时，来自Er离子的荧光峰（EEr）出现共振增强现象，同时来自nc—Si的荧光峰峰值强度则有一定程度的降低。结果表明，nc—Si：Er中的共振增强现象是由于共振激发增强了载流子从nc—Si向临近的Er离子传输过程。

SELECTIVELY-EXCITED PHOTOLUMIN-ESCENCE IN NC-Si:Er

Erbium (Er) doped in nanocrystalline Si (nc-Si:Er) surrounded by SiO2is investigated by selectively-excited photoluminescence(PL) technique. Optical transitions come from nc-Si (peak located at 1 39 eV, denoted as Enc-Si) and Er ions (peak located at 0 81 eV, denoted as EEr) are measured when nc-Si:Er is excited by 1 519 eV or higher excitation photon energy(Eex). Although the Eexof 1 42 eV exceeds the peak energies of Enc-Si and EEr, the Enc-Siand EEremissions are unobserved. A resonant enhancement of the EEremission is observed in nc-Si:Er. While the PL peak intensitiy of the Enc-Sitransition is quenched under this Eex. The resonant-enhanced effect in nc-Si:Er indicates that the energy transfer process of carriers from nc-Si to nearby Er ions is enhanced by resonant excitation.