Ce~(3+)注入对超晶格中硅纳米晶光致发光强度的影响

研究了铈离子注入和二次退火等因素对硅纳米晶(nc-Si)发光强度的影响.利用电子柬蒸发以及高温退火得到nc-Si/SiO2超晶格结构.随后将该结构样晶分别注入2.0×1014cm2和2.0×1015cm-2剂量的铈离子(Ce3+),再分别以不同温度对其进行二次退火,获得多种样品.通过对样品光敏发光光谱的分析发现,Ce3+注入后未经过二次退火的样品发光强度急剧下降.二次退火后的样品,随着退火温度的升高,样品的光致发光灶度逐渐增强,但当温度超过600℃时,发光强度反而下降,600℃为二次退火的最佳退火温度.注入适当剂量的Ce3+,其发光强度可以超过未注入时的发光强度,Ce3+的注入存在饱和剂量.研究表明,样品发光强度的变化受到铈离子注入剂量和注入后二次退火温度等因素的影响,并且存在着Ce3+到nc-Si的能量传递.

Effect of Ce~(3+) Implantation on Photoluminescence Intensity of Si Nanocrystals Embedded in Superlattices

In the present paper, SiO/SiO2 superlattices samples were prepared on Si substrates by electron beam evaporation．The samples were annealed in nitrogen atmosphere at high temperature subsequently．And then, Ce3+ ions with a dose of 2.0×1014 and 2.0×1015 cm-2 respectively were implanted into these samples with formed Si nanocrystals. The photoluminescence (PL) spectra showed that the PL intensities of samples with Ce3+ implanting dropped sharply compared with the samples without Ce3+ implanting. The PL intensity increased gradually with increasing re-annealing temperature, but dropped again when the temperature exceeded 600 ℃. The PL intensity even could be higher than that of samples without Ce3+ implanting if only the dose of Ce3+ was 2.0×1014 cm-2. When the dose of Ce3+ was 2.0×1015 cm-2, the PL intensity couldn’t exceed that of samples without Ce3+ implanting even when the re-annealing temperature was 600 ℃. Further investigations showed that the varieties of the PL intensities were mainly dependent on the re-annealing temperature, which had the best point at 600 ℃, and the dose of Ce3+ had the right value. Furthermore, the experiment results proved that there was energy transfer from Ce3+ to Si nanocrystals in this kind of structure.