Conductive oxide thin films: Model systems for understanding and controlling surface plasmon resonance
Conductive oxide thin films: Model systems for understanding and controlling surface plasmon resonance
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DOI：
10.1063/1.3174440
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发表时间：
2009-07-15
影响因子：
3.2
通讯作者：
Maria, Jon-Paul
中科院分区：
文献类型：
--
作者：
Losego, Mark D.;Efremenko, Alina Y.;Maria, Jon-Paul
简并掺杂的导电氧化物代表了用于探索电荷载流子的性质与其集体等离子体响应之间的相互关系的独特主体。这些材料通常缺乏带间跃迁，这使得元素金属中光谱响应的解释变得模糊，并且与金属不同，导电氧化物的电子输运性质很容易调节。本工作探讨了溅射沉积氧化铟锡（ITO）薄膜中调节表面等离子体共振（SPR）的工艺-结构-性能关系。薄膜沉积条件用于调节薄膜微观结构并将电子迁移率调整到7和40 cm（2）V-1 s（-1）之间。在低氧分压气氛中的沉积后退火用于设计ITO缺陷平衡并将载流子浓度调制到10（20）和10（21）cm（-3）之间。这些电子输运性质调制与近独立性，使直接解释它们的影响，在红外反射率光谱中观察到的SPR响应。较高的电子迁移率有利于较窄的表面等离子体吸收带，而较高的载流子浓度有利于较高的吸收带频率。一个简单的自由电子模型，只有电子载流子密度和电子迁移率作为变量，可以用来描述ITO的介电响应。结合联合收割机的介电函数和菲涅尔方程的计算提供了模拟的反射率光谱，与实验数据相匹配，具有显着的精度。由于这些光谱不使用拟合参数，并且是用经过充分研究的材料特性计算的，因此它为先进材料系统（包括简并掺杂半导体、硅化物和氮化物）中等离子体响应的未来设计提供了机会。(C)2009年美国物理学会。[DOI：10.1063/1.3174440]
Degeneratively doped conductive oxides represent a unique host for exploring the inter-relationship between the properties of charge carriers and their collective plasmonic response. These materials often lack interband transitions that obfuscate interpretation of spectral response in elemental metals, and unlike metals, the electronic transport properties of conductive oxides are easily tunable. This work explores the process-structure-property relationships that regulate surface plasmon resonance (SPR) in sputter deposited indium tin oxide (ITO) thin films. Film deposition conditions are used to regulate film microstructure and tune the electronic mobility to between 7 and 40 cm(2) V-1 s(-1). Postdeposition annealing in low oxygen partial pressure atmospheres is used to engineer the ITO defect equilibrium and modulate carrier concentrations to between 10(20) and 10(21) cm(-3). These electronic transport properties are modulated with near independence enabling straightforward interpretation of their influence on the SPR response observed in the infrared reflectivity spectrum. Higher electronic mobilities favor narrower surface plasmon absorption bands, while higher carrier concentrations favor higher absorption band frequencies. A simple free electron model, having only electronic carrier density and electronic mobility as variables, can be used to describe ITO's dielectric response. Calculations that combine this dielectric function and the Fresnel equations provide simulated reflectivity spectra that match experimental data with remarkable accuracy. Because these spectra use no fitting parameters and are calculated with well-studied material properties, it opens the opportunity for future design of plasmonic response in advanced material systems including degeneratively doped semiconductors, silicides, and nitrides. (C) 2009 American Institute of Physics. [DOI: 10.1063/1.3174440]