金属银衬底对氧化锌微腔光致发光特性的影响

发布时间：2018-06-25 07:30

  本文选题：金属等离激元 + 激子极化激元　； 参考：《南京大学》2015年硕士论文

【摘要】：在过去的二十年里平板微腔中激子和光子的耦合一直是人们研究的热点。最开始是用分布式布拉格反射镜(DBRs)作为反射面形成的微腔,后来出现用金属镜代替DBRs。相比其他各种平板微腔,半导体微腔在激子和光子耦合的研究和应用中有极大的优势,它同时提供了光学限制腔和激子。而且随着纳米材料制备技术的进步,半导体微腔制备工艺简单,品质质量高,形式结构多样等优点进一步突显出来了。由于具有大的激子束缚能(-60meV)氧化锌材料构成的微腔在室温下就能实现激子极化激元,在光电子器件和半导体激光器等领域展现出极大的应用前景。另一方面,金属表面等离激化基元(SPPs)可以打破衍射极限的限制,为亚波长光学研究打开了大门。已有研究发现,在半导体微腔中引入SPPs会对半导体微腔的光学性质产生很大的影响。我们用不同的生长机制制备了氧化锌纳米线和微米棒。最终我们选用直径达到几微米的氧化锌微米棒作为光学微腔。通过把氧化锌微米棒转移到四电极银衬底上,做出一半悬空一半与金属银衬底接触的实验样品。用共聚焦显微镜测量得到同一个氧化锌微米棒底面分别与金属银接触和不接触的相邻两点处的光致发光光谱。通过光谱图中的共振模式可以得到两处的色散曲线。我们引入激子极化激元理论中描述激子光子相互作用中的振子强度增强倍数的参数Γ,发现当取合适的数值时,我们从光谱图得到的实验上的色散关系和激子极化激元理论上的色散关系吻合的很好。这说明了在室温下,我们的样品中激子和F-P腔模式中的光子发生了很强的耦合作用。而且我们发现和金属银衬底接触和悬在空气中的相邻两点处的振子强度增强倍数11分别是1.96和1.68。可以发现金属银衬底增强了激子和光子的耦合。我们也测量到了垂直入射时氧化锌金属银界面的反射相位,在416rnm波长时是-0.77π,这与我们从折射率数据库查到的空气银界面在相同波长-0.72π反射相位很相近。
[Abstract]:The coupling of excitons and photons in plate microcavities has been a hot topic in the past two decades. At first, distributed Bragg reflector (DBRs) was used as the reflection surface of microcavity, then metal mirror was used instead of DBRs. Compared with other planar microcavities, semiconductor microcavities have great advantages in the research and application of exciton and photon coupling, which provide both optical confinement resonators and excitons at the same time. Along with the progress of preparation technology of nanomaterials, the advantages of simple preparation process, high quality and various forms of semiconductor microcavity have been further highlighted. Because the micro-cavity with large exciton binding energy (-60 MEV) zinc oxide can realize the exciton polarization at room temperature, it has shown great application prospect in the fields of optoelectronic devices and semiconductor lasers. On the other hand, the SPPs can break the limit of diffraction limit and open the door for the study of subwavelength optics. It has been found that the introduction of SPPs into semiconductor microcavities has great influence on the optical properties of semiconductor microcavities. Zinc oxide nanowires and micron rods were prepared by different growth mechanisms. Finally, we choose zinc oxide micron rod with diameter of several microns as optical microcavity. By transferring zinc oxide micron rods onto a four-electrode silver substrate, an experimental sample of half suspended and half in contact with the metal silver substrate was made. The photoluminescence spectra of the two adjacent two points of the same zinc oxide micron rod surface in contact with and without contact with silver were measured by confocal microscope. Two dispersion curves can be obtained by resonant modes in the spectrogram. In this paper, we introduce the parameter 螕 to describe the intensity enhancement multiple of the oscillator in the exciton photon interaction by introducing the exciton polarization theory. It is found that when the appropriate numerical value is taken, The experimental dispersion relation obtained from the spectral diagram is in good agreement with the theoretical dispersion relationship of exciton polariton. This shows that the exciton in our sample and the photons in the F-P cavity mode are strongly coupled at room temperature. Furthermore, we find that the intensities of the oscillator in contact with and suspended in the air at two adjacent points are 1.96 and 1.68 respectively. It can be found that the coupling of excitons and photons is enhanced by metallic silver substrates. We have also measured the reflection phase of the interface of zinc oxide metal silver at the vertical incidence, which is -0.77 蟺 at the 416rnm wavelength, which is very close to the reflection phase of the air-silver interface found from the refractive index database at the same wavelength -0.72 蟺.
【学位授予单位】：南京大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ132.41
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本文编号：2065153