采用同步辐射白光貌相术研究了快速降温温度梯度法合成的大颗粒金刚石单晶体的晶体缺陷.晶体生长的早期形成了沿±[ 100]和±[010]方向延伸的平直位错,位错线均起源于种晶表面.晶体生长中期向[001]方向生长,未生成新位错.在晶体生长的末期,形成了大量位错束,这些位错束由多条直线形位错组成,每个位错束中的所有位错生成于同一位错源,分布在扇形区域内,扇形夹角大多数在30.以内.这些扇形位错束的位错源均位于靠近晶体外表面的晶体内,在靠近(100)的晶面附近分布最多,(100)晶面附近比较多.少部分靠近(010)和(010)晶面.位错束的生长方向主要分布在[100]至[101]区域和[001]附近区域,少量向[010]、[010]方向延伸.位错束的形成和晶体合成末期的快速降温具有密切的关系.%The defects in a large diamond crystal synthesized by HPHT temperature gradient method with rapid descent of temperature were studied using white synchrotron radiation topography. Dislocations which originated from the surfaces of the seed and extended along the directions of ± [100] and ± [010] were observed within the crystal grown at the early stage. The crystal was then grown to the [001 ] direction at the middle growing stage and no dislocations were found generated at this stage. A lot of dislocation bundles were generated at the last growth stage of the crystal and each bundle was composed of many straight extended dislocations originated from the same point and extended radially within a sector about 30°. The origins of the dislocation bundles was distributed near the surface of the crystal. Most of the dislocation bundles were generated near the (100) and those near the (100) were in the second place, and still there were some existing near the crystal face (010)rnand (010). The growth directions of the dislocation bundles was mainly within the range from[ 100] to[101] and near the direction[001 ]. Also, few of the dislocation bundles were found directing to[010] and[010]. The generation of the dislocation bundles was associated with the rapid descent of the temperature in the last growth slage of the diamond crystal.
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