Abstract Transparent conductive oxides have been widely applied to solar cells, liquid crystal displays, and other optoelectronic devices because of their excellent transparent conductive properties in the visible-near-infrared (Vis-NIR) region. At present, the transparent conductive oxide films (TCOFs) such as indium tin oxide (ITO), fluorine-doped tin oxide (FTO), and aluminum-doped zinc oxide (AZO) are widely noticed and used. However, a high carrier concentration (≥1020 cm−3) of these TCOFs leads to a result that their transparency will be affected by the plasmons effect, and thus their transparent range will generally end around 2–3 μm. As such, they are more applicable in the Vis-NIR region but unable to meet the requirements of mid-infrared (MIR) optoelectronic devices. Faced with this situation, herein, we reported the native ZnO bulk single crystals with low background carrier concentration (1015–1016 cm−3) and high carrier mobility (μ > 300 cm2 V−1 s−1). These single crystals boast excellent transparent conductive properties (IR cutoff edge: 6–8 μm, Rsheet: 3.7–28.5 Ω/sq) with an advantage that they can be massively produced by a hydrothermal method at a low cost. Based on these merits, the native ZnO bulk single crystals bring a new possibility of breaking the bottleneck of MIR transparent conductivity.

中文翻译：

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超宽光谱范围（0.4-8 μm）透明导电块状单晶 ZnO 晶体：中红外光电子学的领跑者

摘要 透明导电氧化物因其在可见-近红外（Vis-NIR）区域具有优异的透明导电性能而被广泛应用于太阳能电池、液晶显示器等光电器件中。目前，氧化铟锡（ITO）、掺氟氧化锡（FTO）、掺铝氧化锌（AZO）等透明导电氧化物薄膜（TCOFs）受到广泛关注和应用。然而，这些TCOFs的高载流子浓度（≥1020 cm-3）导致它们的透明度会受到等离子体效应的影响，因此它们的透明范围通常会在2-3 μm左右结束。因此，它们更适用于 Vis-NIR 区域，但无法满足中红外 (MIR) 光电器件的要求。面对这种情况，在此，我们报告了具有低背景载流子浓度 (1015–1016 cm-3) 和高载流子迁移率 (μ > 300 cm2 V-1 s-1) 的天然 ZnO 块状单晶。这些单晶具有优异的透明导电性能（红外截止边缘：6-8 μm，Rsheet：3.7-28.5 Ω/sq），优势在于它们可以通过水热法以低成本大规模生产。基于这些优点，原生ZnO块状单晶为打破中红外透明导电性瓶颈带来了新的可能性。