Microvoid formation in hydrogen-implanted ZnO probed by a slow positron beam
Microvoid formation in hydrogen-implanted ZnO probed by a slow positron beam
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DOI：
10.1103/physrevb.71.115213
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发表时间：
2005-03-01
影响因子：
3.7
通讯作者：
Ohdaira, T
中科院分区：
文献类型：
--
作者：
Chen, ZQ;Kawasuso, A;Ohdaira, T
用20-80 keV的氢离子注入ZnO晶体，总剂量为4.4 × 10 ~（15）cm ~（-2）。正电子寿命和多普勒展宽的湮没辐射测量表明，引入锌空位相关的缺陷后，注入。发现这些空位被氢原子填充。在200-500 ℃的等时退火后，空位聚集成氢气泡。在600-700摄氏度的进一步退火导致氢气从气泡中释放出来，留下大量的微孔。这些微孔在1000摄氏度的高温下退火。注入样品的拉曼光谱显示在约575 cm（-1）处的振动模式增强，这表明引入了氧空位。这些氧空位在600-700摄氏度的温度下消失，这应该有助于氢气泡的形成。阴极射线发光测量表明，氢离子也钝化深能级发射中心之前，他们从样品中释放，导致改善的UV发射。
ZnO crystals were implanted with 20-80 keV hydrogen ions up to a total dose of 4.4x10(15) cm(-2). Positron lifetime and Doppler broadening of annihilation radiation measurements show introduction of zinc vacancy-related defects after implantation. These vacancies are found to be filled with hydrogen atoms. After isochronal annealing at 200-500 degrees C, the vacancies agglomerate into hydrogen bubbles. Further annealing at 600-700 degrees C causes release of hydrogen out of the bubbles, leaving a large amount of microvoids. These microvoids are annealed out at high temperature of 1000 degrees C. Raman spectroscopy for the implanted sample shows the enhancement of vibration modes at about 575 cm(-1), which indicates introduction of oxygen vacancies. These oxygen vacancies disappear at temperatures of 600-700 degrees C, which is supposed to contribute to the hydrogen bubble formation. Cathodoluminescence measurements reveal that hydrogen ions also passivate deep level emission centers before their release from the sample, leading to the improvement of the UV emission.