Er^(3+)和Eu^(3+)共注入GaN的光学特性和能量传递机制

Optical Properties and Energy Transfer Mechanism in Er^(3+) and Eu^(3+) Co-doped GaN Films

采用离子注入法在GaN薄膜中实现了Er^(3+)和Eu^(3+)离子的共掺杂.以阴极荧光光谱仪为主要表征手段,研究样品的光学特性和能量传递机理.在300K温度下,Er^(3+)和Eu^(3+)共掺杂GaN薄膜能够实现绿光和红光的同时发射.随着Er^(3+)离子掺杂剂量的增加,Eu^(3+)离子相关发光峰的强度减弱,Er^(3+)离子对应的两个相关发光峰强度比值减小,表明Er^(3+)和Eu^(3+)离子之间发生了能量传递,能量传递的方向为Eu^(3+)→Er^(3+).变温阴极荧光光谱显示,Er^(3+)离子的2H11/2和4S3/2两个能态相关的跃迁峰相对强度比值随着温度升高而降低,主要是由两个能级之间的热耦合导致.改变Er^(3+)离子的掺杂剂量,能够调控GaN:Er^(3+)/Eu^(3+)样品的光学色度坐标和色温,表明此材料可用于发光器件.

The samples of Er^3＋and Eu^3＋co-doped GaN epitaxial films were prepared by ion implantation technique. Their optical properties and energy transfer mechanism were investigated using cathodoluminescence.For Er^3＋and Eu^3＋co-doped GaN films sample,the mixed color of green and red light can be realized at 300 K.Moreover,the emission intensity of Eu^3＋ions and intensity ratio of Er^3＋ions were decreased with the increase of Er^3＋ions implantation dose,which proved the existence of the energy transfer from Eu^3＋to Er^3＋in the GaN host. The result of temperature-dependent cathodoluminescence spectra shows that the intensity ratio is decreased with the temperature increasing,which indicates there is a thermal coupling of 2 H11/2 and 4 S3/2 states of Er^3＋ions.The calculated chromaticity coordinates and color correlated temperature can be tuned through adjusting the implantation dose ratio of Er^3＋to Eu^3＋.This work shows Er^3＋and Eu^3＋co-doped GaN films are promising materials applied in optical devices.