Direct Optical Lithography of Colloidal Metal Oxide Nanomaterials for Diffractive Optical Elements with 2π Phase Control
Direct Optical Lithography of Colloidal Metal Oxide Nanomaterials for Diffractive Optical Elements with 2π Phase Control
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DOI：
10.1021/jacs.0c12447
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发表时间：
2021-01-28
影响因子：
15
通讯作者：
Talapin, Dmitri, V
中科院分区：
文献类型：
--
作者：
Pan, Jia-Ahn;Rong, Zichao;Talapin, Dmitri, V
空间图案介电材料在电子、光子和光电器件中无处不在。这些图案通常是通过利用气相试剂的减法或加法方法制成的。另一方面，氧化物纳米材料溶液相合成的最新进展解锁了具有更大成分、微观结构和界面可调性的材料库。然而，在现实设备中对这些纳米材料进行图案化和集成的方法尚未建立。在这项工作中，我们通过将氧化物纳米颗粒 (NP) 与光敏重氮-2-萘酚-4-磺酸混合并用广泛可用的 405 nm 光照射来直接光学图案化。我们演示了 ZrO2、TiO2、HfO2 和 ITO NP 的直接光学光刻，并研究了导致这种光致溶解度降低的化学和物理变化。微米厚的非晶 ZrO2 纳米粒子层以微米分辨率进行图案化，并显示可以对可见光进行 2 pi 相位控制。我们还展示了多层图案，并用它来制造具有不同厚度和不同结构颜色的特征。在 400 摄氏度退火后，沉积的 ZrO2 结构在较宽的波长范围（0.3-10 μm）内具有优异的光学透明度、高折射率（633 nm 处 n = 1.84），并且光学平滑。然后，我们制造了衍射光学元件，例如二元相位衍射光栅，它表现出高效的衍射行为和良好的热稳定性。不同的氧化物纳米粒子也可以在图案化之前混合，从而提供高水平的材料可调性。这项工作展示了一种通用的图案化方法，该方法利用胶体氧化物纳米材料的可加工性和多样性用于光子应用。
Spatially patterned dielectric materials are ubiquitous in electronic, photonic, and optoelectronic devices. These patterns are typically made by subtractive or additive approaches utilizing vapor-phase reagents. On the other hand, recent advances in solution-phase synthesis of oxide nanomaterials have unlocked a materials library with greater compositional, microstructural, and interfacial tunability. However, methods to pattern and integrate these nanomaterials in real-world devices are less established. In this work, we directly optically pattern oxide nanoparticles (NPs) by mixing them with photosensitive diazo-2-naphthol-4-sulfonic acid and irradiating with widely available 405 nm light. We demonstrate the direct optical lithography of ZrO2, TiO2, HfO2, and ITO NPs and investigate the chemical and physical changes responsible for this photoinduced decrease in solubility. Micron-thick layers of amorphous ZrO2 NPs were patterned with micron resolution and shown to allow 2 pi phase control of visible light. We also show multilayer patterning and use it to fabricate features with different thicknesses and distinct structural colors. Upon annealing at 400 degrees C, the deposited ZrO2 structures have excellent optical transparency across a wide wavelength range (0.3-10 mu m), a high refractive index (n = 1.84 at 633 nm), and are optically smooth. We then fabricate diffractive optical elements, such as binary phase diffraction gratings, that show efficient diffractive behavior and good thermal stability. Different oxide NPs can also be mixed prior to patterning, providing a high level of material tunability. This work demonstrates a general patterning approach that harnesses the processability and diversity of colloidal oxide nanomaterials for use in photonic applications.