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采用物理气相传输(PVT)法制备大尺寸硫化镉(CdS)籽晶,通过调整源区与生长区温差进行了籽晶扩大实验,并进行了X射线衍射(XRD)、红外透过率和腐蚀坑密度等测试。研究表明,在15,10,5和2℃等不同温差条件下,均可实现CdS籽晶的扩展,扩展的晶体区域具有和初始籽晶相同的晶向,而且低温差利于获得更大的单晶扩展面积。当温差为5℃时,扩展出的CdS单晶的X射线衍射半高宽(FWHM)较小、红外透过率较高且腐蚀位错密度较低,表明此时晶体的质量较好;当温差增大为10℃和15℃时,蒸气过饱和度高、晶体生长速率大,导致晶体质量变差;当温差减小为2℃时,晶体生长驱动力不足,这容易形成不稳定的生长界面并导致晶体质量下降。
Large size CdS seed crystals were prepared by physical vapor deposition (PVT) method. The seed crystal growth experiments were carried out by adjusting the temperature difference between the source and the growth regions. XRD, IR and corrosion Pit density test. The results show that the growth of CdS seeds can be achieved under different temperature conditions of 15, 10, 5 and 2 ℃, etc. The extended crystal region has the same orientation as the original seed and the low temperature difference is conducive to obtaining a larger single Crystal expansion area. When the temperature difference is 5 ℃, the extended FWHM of the CdS single crystal is smaller, the infrared transmittance is higher and the corrosion dislocation density is lower, indicating that the crystal quality is good at this time. When When the temperature difference is increased to 10 ° C and 15 ° C, the vapor supersaturation is high and the crystal growth rate is large, resulting in deterioration of the crystal quality. When the temperature difference is decreased to 2 ° C, the crystal growth driving force is insufficient, which easily results in unstable growth Interface and lead to crystal quality decline.