Sharma Madan, Singh Aditya, Aggarwal Pallavi, Singh Rajendra
Department of Physics, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India.
Department of Electrical Engineering, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India.
ACS Omega. 2022 Apr 2;7(14):11731-11741. doi: 10.1021/acsomega.1c06855. eCollection 2022 Apr 12.
Layer transfer offers enormous potential for the industrial implementation of two-dimensional (2D) material technology platforms. However, the transfer method used must retain the as-grown uniformity and cleanliness in the transferred films for the fabrication of 2D material-based devices. Additionally, the method used must be capable of large-area transfer to maintain wafer-scale fabrication standards. Here, a facile route to transfer centimeter-scale synthesized 2D transition metal dichalcogenides (TMDCs) (3L MoS, 1L WS) onto various substrates such as sapphire, SiO/Si, and flexible substrates (mica, polyimide) has been developed using a water-soluble layer (NaS/NaSO) underneath the as-grown film. The developed transfer process represents a fast, clean, generic, and scalable technique to transfer 2D atomic layers. The key strategy used in this process includes the dissolution of the NaS/NaSO layer due to the penetration of NaOH solution between the growth substrate and hydrophobic 2D TMDC film. As a proof-of-concept device, a broadband photodetector has been fabricated onto the transferred 3L MoS, which shows photoresponse behavior for a wide range of wavelengths ranging from near-infrared (NIR) to UV. The enhancement in photocurrent was found to be 100 times and 10 times the dark current in the UV and visible regions, respectively. The fabricated photodetector shows a higher responsivity of 8.6 mA/W even at a low applied voltage (1.5 V) and low power density (0.6 μW/mm). The detector enables a high detectivity of 2.9 × 10 Jones. This work opens up the pathway toward flexible electronics and optoelectronics.
层转移为二维（2D）材料技术平台的工业应用提供了巨大潜力。然而，所使用的转移方法必须在转移后的薄膜中保持生长时的均匀性和清洁度，以用于制造基于二维材料的器件。此外，所使用的方法必须能够进行大面积转移，以维持晶圆级制造标准。在此，已开发出一种简便的方法，通过在生长的薄膜下方使用水溶性层（NaS/NaSO），将厘米级合成的二维过渡金属二硫属化物（TMDCs）（3L MoS、1L WS）转移到各种衬底上，如蓝宝石、SiO/Si以及柔性衬底（云母、聚酰亚胺）。所开发的转移工艺代表了一种快速、清洁、通用且可扩展的二维原子层转移技术。该工艺中使用的关键策略包括由于NaOH溶液渗透到生长衬底和疏水性二维TMDC薄膜之间而导致NaS/NaSO层溶解。作为概念验证器件，已在转移后的3L MoS上制造了宽带光电探测器，该探测器在从近红外（NIR）到紫外的广泛波长范围内均表现出光响应行为。发现光电流在紫外和可见光区域分别比暗电流增强了100倍和10倍。所制造的光电探测器即使在低施加电压（1.5 V）和低功率密度（0.6 μW/mm）下也显示出8.6 mA/W的更高响应度。该探测器实现了2.9×10 Jones的高探测率。这项工作为柔性电子学和光电子学开辟了道路。
