IMEC, Kapeldreef 75, Leuven, B3001, Belgium.
Nanoscale. 2016 Jun 16;8(24):12324-9. doi: 10.1039/c6nr01837h.
We present distinct asymmetric plasmon-induced noise properties of ionic transport observed through gold coated nanopores. We thoroughly investigated the effects of bias voltage and laser illumination. We show that the potential drop across top-coated silicon nanocavity pores can give rise to a large noise asymmetry (∼2-3 orders of magnitude). Varying the bias voltage has an appreciable effect on the noise density spectra, typically in the Lorentzian components. The laser power is found to strongly affect the ionic noise level as well as the voltage threshold for light-induced noise generation. The asymmetric noise phenomenon is attributed to plasmon-induced interfacial reactions which promote light-induced charge fluctuation in the ion flow and allow voltage modulation of photo-induced carriers surmounting over such Schottky junctions. We further compare the ionic noise performances of gold nanocavities containing different material stacks, among which thermal oxide passivation of the silicon successfully mitigates the light-induced noise and is also fully CMOS-compatible. The understanding of the described noise characteristics will help to foster multiple applications using related structures including plasmonic-based sensing or plasmon-induced catalysis such as water splitting or solar energy conversion devices.
我们展示了通过金覆盖的纳米孔观察到的离子传输的独特不对称等离子体诱导噪声特性。我们彻底研究了偏置电压和激光照射的影响。我们表明，顶部涂覆硅纳米腔孔的电势降可能导致大的噪声不对称性（约 2-3 个数量级）。改变偏置电压对噪声密度谱有明显影响，通常在洛伦兹分量中。发现激光功率强烈影响离子噪声水平以及光致噪声产生的电压阈值。不对称噪声现象归因于等离子体诱导的界面反应，该反应促进了离子流中的光致电荷波动，并允许光致载流子的电压调制克服这种肖特基结。我们进一步比较了含有不同材料堆叠的金纳米腔的离子噪声性能，其中硅的热氧化钝化成功地减轻了光致噪声，并且完全与 CMOS 兼容。对所描述的噪声特性的理解将有助于促进使用相关结构的多种应用，包括基于等离子体的传感或等离子体诱导的催化，如水分解或太阳能转换设备。
