【摘要】 在ZnO单晶样品中注入了能量为20—100keV、总剂量为4.4×1015cm-2的He离子.利用基于慢正电子束的多普勒展宽测量研究了离子注入产生的缺陷.结果表明,He离子注入ZnO产生了双空位或更大的空位团.在400℃以下退火后,He开始填充到这些空位团里面,造成空位团的有效体积减少.经过400℃以上升温退火后,这些空位团的尺寸开始增大,但由于有少量的He仍然占据在空位团内,因此直到800℃这些空位团仍保持稳定.高于800℃退火后,由于He的脱附,留下的空位团很快回复,在1000℃下得到完全消除.更多还原

【Abstract】 ZnO single crystals were implanted with He ions of energy of 20—100?keV. The total implantation dose was 4.4×10 15 ?cm -2 . Doppler broadening of positron annihilation spectra were measured using a slow positron beam to study the implantation-induced defects. The results suggest that after implantation, divacancies or larger vacancy clusters are produced. After annealing below 400?℃, He impurity begins to occupy the vacancy clusters. Upon further annealing above 400?℃, the vacancy clusters grow in size. At annealing temperature of above 800?℃, He atom is released from the vacancy clusters, and the vacancies begin to recover and are annealed out at 1000?℃.更多还原