高温退火对MgO晶体光致发光性能的影响

利用自行搭建的实验平台,测试了高纯MgO晶体和Sc掺杂MgO晶体的紫外光光致发光(PL)光谱,发射峰值分别位于389.31、498.61nm、712.44和749.06nm,其可见光发射区和红外发射区主要对应于MgO晶体中由O空位构成的F色心和F+色心通过激发和退激发机制发射;在不同温度退火条件下测试Sc掺杂MgO晶体的PL光谱,并利用高斯分解实现了Sc掺杂MgO晶体中F色心和F+色心的定位。结果表明,高温退火处理可以有效降低MgO晶体表面的污染,进而提高晶体的光电活性;Sc掺杂导致MgO晶体可见光发射区域的蓝移和增强,其中F+色心对于温度的依赖性较强。

High temperature annealing effect on PL characteristic of MgO crystals

UV luminescence spectra of high purity MgO crystals and Sc doped MgO crystals were tested by self-built experiment platform.The crystals were expose d to vacuum ultraviolet radiation first,and then the emission spectra were tested under different annealing temperatures.The emission peaks are located at 389.31nm,498.61nm, 712.44nm and 749.06nm respectively,which have great accordance wit h the calculation results got by first-principles.The visible emission region and infrared emis sion region are attributed to F and F+ color centers constituted by oxygen vacancy lo cated in MgO crystal.The excitation and relaxation mechanisms caused by electrons emit ted from color center and trapped by color center play an important role for these emission regions.Furthermore,we tested photoluminescence spectra of Sc doped crystals under different annealing temperatures,and F color center and F⁺ colo r center of crystals are located by Gauss decomposition.The results show that high tempera ture annealing treatment not only reduces the MgO crystal surface contamination but a lso increases the optical activity of crystal.Meanwhile,Sc doping leads to the enhan cement and blue shift of visible light emission region in crystal,while F ⁺ color center has more strong temperature dependence.