This study reports on the mid-infrared (mid-IR) photothermal response of multilayer MoS₂ thin films grown on crystalline (p-type silicon and c-axis-oriented single crystal sapphire) and amorphous (Si/SiO₂ and Si/SiN) substrates by pulsed laser deposition (PLD). The photothermal response of the MoS₂ films is measured as the changes in the resistance of the MoS₂ films when irradiated with a mid-IR (7 to 8.2 μm) source. We show that enhancing the temperature coefficient of resistance (TCR) of the MoS₂ thin films is possible by controlling the film-substrate interface through a proper choice of substrate and growth conditions. The thin films grown by PLD are characterized using X-ray diffraction, Raman, atomic force microscopy, X-ray photoelectron microscopy, and transmission electron microscopy. The high-resolution transmission electron microscopy (HRTEM) images show that the MoS₂ films grow on sapphire substrates in a layer-by-layer manner with misfit dislocations. The layer growth morphology is disrupted when the films are grown on substrates with a diamond cubic structure (e.g., silicon) because of twin growth formation. The growth morphology on amorphous substrates, such as Si/SiO₂ or Si/SiN, is very different. The PLD-grown MoS₂ films on silicon show higher TCR (−2.9% K⁻¹ at 296 K), higher mid-IR sensitivity (ΔR/R = 5.2%), and higher responsivity (8.7 V·W^–1) compared to both the PLD-grown films on other substrates and the mechanically exfoliated MoS₂ flakes transferred to different substrates.

中文翻译：

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界面对脉冲激光沉积生长的MoS 2薄膜的中红外光热响应的影响

这项研究报告了晶体（p型硅和c轴取向单晶蓝宝石）和非晶（Si / SiO ₂和Si / SiN ）上生长的多层MoS ₂薄膜的中红外（mid-IR）光热响应）脉冲激光沉积（PLD）。将MoS ₂膜的光热响应测量为当用中红外（7至8.2μm）光源照射时MoS ₂膜的电阻变化。我们表明，增强MoS ₂的电阻温度系数（TCR）薄膜通过控制经过的衬底和生长条件适当选择薄膜-衬底界面是可能的。使用X射线衍射，拉曼光谱，原子力显微镜，X射线光电子显微镜和透射电子显微镜对通过PLD生长的薄膜进行表征。高分辨率透射电子显微镜（HRTEM）图像显示，MoS ₂膜以错配位错的逐层方式生长在蓝宝石衬底上。当膜在具有菱形立方结构的基板（例如硅）上生长时，由于双晶生长的形成，层的生长形态被破坏。在诸如Si / SiO ₂或Si / SiN的非晶衬底上的生长形态非常不同。PLD生长的MoS ₂与PLD-PLD-PLD和PLD-PLD-PLD相比，硅薄膜都显示出更高的TCR（在2.9 K时为-2.9％K ^-1），更高的中红外灵敏度（ΔR / R = 5.2％）和更高的响应度（8.7 V·W ^–1）。在其他基材上生长的薄膜以及将机械剥离的MoS ₂薄片转移到不同的基材上。