YAP晶体变色现象的研究

Study on the Color Change of YAP Crystals

YAlO3(YAP)晶体具有优良的物理和化学性能 ,在许多方面都有广泛的应用前景。我们在对闪烁晶体Ce∶YAP的研究过程中 ,发现了YAP晶体的变色现象。本文利用晶体透过谱对其颜色的变化进行了研究。不同的退火气氛及不同的掺杂成份对晶体颜色有较大影响 ,H2 气氛退火或掺杂Ce元素使晶体颜色变浅 ,而在空气中退火或掺杂Yb元素则使晶体颜色加深。针对这一变色现象 ,我们认为是在晶体生长过程由于电荷补偿的需要而产生的O-心的吸收作用导致的。不同的O-心浓度其吸收作用不同 ,从而使晶体在 40 0nm附近的透过率发生变化。采用这一模型可以对晶体颜色的变化及不同退火条件和掺杂元素的影响作出合理的解释。

YAlO 3(YAP) crystal has been widely investigated in various fields because of its favourable physical and chemical properties. In our research on scintillation crystal of Ce∶YAP,a peculiar phenomenon of color change in YAP crystal was found. In this article,we studied this phenomenon by means of transmission spectra and found that different anneal conditions and different dopants could greatly influence the colors. Anneal in H 2 or Ce dopant could reduce the colors and anneal in atmosphere or Yb dopant could make the colors deeper.We think this color change should be ascribed to the electron trap O- centers produced in crystal growth due to the charge compensation.The absorption effect of O- centers lead to the change of the crystal transmission at about 400nm. All the phenomena could be reasonably interpreted with this model.