Er离子注入的富硅SiO_2 MOS-LED的可见和红外电致发光特性

Visible and Infrared Electroluminescence Property of Erbium Doped Silicon-rich SiO_2 MOS-LED

通过Er离子和Si离子注入并结合高温退火制备了Er掺杂的富硅SiO2薄膜以及ITO/SiON/富硅SiO2∶Er/Si MOS结构电致发光器件。研究了富Si浓度的变化对Er3+离子掺杂的电致发光器件的发光性能和传导特性的影响。发现不同Si含量对Er3+离子的不同能级的电致发光会产生不同作用。在富Si量小于5%的条件下,主要由Si离子注入产生氧空位缺陷发光中心(Si-ODC),它们和Er3+离子的高能级之间存在着共振能量传递,增强了Er3+离子的522 nm绿色发光峰强度。在富Si含量大于5%时,过量的Si在退火时形成了纳米硅微晶,电子在纳米硅微晶之间的隧穿改变了载流子输运机制,降低了过热电子的平均能量,导致Er3+离子的所有发光峰的猝灭。

Metal-oxide-semiconductor structure of ITO/Si-rich SiO2∶Er/Si containing erbium ions and silicon nanocrystals was fabricated by ion implantation of Si and Er combined with post-annealing.The electroluminescence spectra and current-voltage characteristics were measured to investigate the influence of silicon concentration on the excitation mechanism of luminescence centers and conductance process.It was found that the excitation mechanism of erbium ions was variational in the MOS-LED with silicon content.For the silicon concentration less than 5%,the upper levels of erbium can be excited by resonant energy transfer from silicon-oxygen deficiency centers,which induce an enhancement of the 522 nm peak emission intensity of Er3＋ ion.For the silicon concentration above 5%,the excess silicon formed silicon nanocrystals by post-annealing.The direct tunneling of electrons between silicon nanocrystals dominate the conductance,resulting a decrease of average energy of hot electrons and quenching of all the electroluminescence peaks of erbium.