Department of Physics, Centre for Materials Science and Nanotechnology, University of Oslo, P.O. Box 1048 Blindern, N-0316, Oslo, Norway.
Sci Rep. 2018 Jan 16;8(1):848. doi: 10.1038/s41598-017-18949-9.
Recent progresses in nanoscale semiconductor technology have heightened the need for measurements of band gaps with high spatial resolution. Band gap mapping can be performed through a combination of probe-corrected scanning transmission electron microscopy (STEM) and monochromated electron energy-loss spectroscopy (EELS), but are rare owing to the complexity of the experiments and the data analysis. Furthermore, although this method is far superior in terms of spatial resolution to any other techniques, it is still fundamentally resolution-limited due to inelastic delocalization of the EELS signal. In this work we have established a quantitative correlation between optical band gaps and plasmon energies using the ZnCd O/ZnO system as an example, thereby side-stepping the fundamental resolution limits of band gap measurements, and providing a simple and convenient approach to achieve band gap maps with unprecedented spatial resolution.
纳米级半导体技术的最新进展，提高了对高空间分辨率能带隙测量的需求。能带隙测绘可以通过探针校正扫描透射电子显微镜（STEM）和单色电子能量损失谱（EELS）的组合来完成，但由于实验和数据分析的复杂性，这种方法很少见。此外，尽管这种方法在空间分辨率方面远远优于任何其他技术，但由于 EELS 信号的非弹性离域，它仍然受到基本分辨率的限制。在这项工作中，我们以 ZnCdO/ZnO 系统为例，建立了光学带隙和等离子体能量之间的定量关系，从而避开了带隙测量的基本分辨率限制，并提供了一种简单方便的方法，以实现具有前所未有的空间分辨率的带隙图谱。
