Surface Diffusion-Limited Growth of Large and High-Quality Monolayer Transition Metal Dichalcogenides in Confined Space of Microreactor
Surface Diffusion-Limited Growth of Large and High-Quality Monolayer Transition Metal Dichalcogenides in Confined Space of Microreactor
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微反应器密闭空间中大尺寸、高质量单层过渡金属二硫属化物的表面扩散限制生长
DOI：
10.1021/acsnano.2c05076
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发表时间：
2022
期刊：
影响因子：
17.1
通讯作者：
Hayashi Yasuhiko
中科院分区：
文献类型：
--
作者：
Suzuki Hiroo;Hashimoto Ryoki;Misawa Masaaki;Liu Yijun;Kishibuchi Misaki;Ishimura Kentaro;Tsuruta Kenji;Miyata Yasumitsu;Hayashi Yasuhiko
过渡金属二硫属化合物（TMDCs），包括MoS 2和WS 2，由于其原子薄的结构和强的光电响应，使得其具有灵活的光电应用，是下一代半导体材料的潜在候选者。单层TMDC已经利用化学气相沉积（CVD）技术生长。在高结晶度下增加电畴尺寸和形成异质结构是实际应用中的重要课题。在这项研究中，单层WS 2的尺寸增加，通过气-液-固生长为基础的CVD技术，利用有限的空间的基板堆叠微反应器。旋涂金属盐（Na 2 WO 4和Na 2 MoO 4）和有机硫蒸汽的使用使我们能够精确地控制源供应，并以系统的方式研究生长。我们得到了一个相对较低的活化能的增长（1.02 eV），这是符合在有限空间中观察到的表面扩散限制的生长制度。通过系统的光致发光（PL）分析，我们确定，820 °C的生长温度是最佳的生产高品质的WS 2与窄PL峰宽（35 meV）。通过控制W和S的源平衡，我们得到了大尺寸的单层WS 2（约560 μm）和单层WS 2双层斑点（约1100 μm）。结合两种不同的过渡金属源，成功地创建了WS 2/MoS 2横向异质结构。在电输运测量中，在最佳条件下生长的单层WS 2具有高的开/关电流（~ 70 μA/μm）、开/关比（~ 50 × 108）和场效应迁移率（~ 70 cm 2/（Vs））。场效应晶体管显示出固有的光响应与波长的选择性，起源于光激发的载流子。
Transition metal dichalcogenides (TMDCs), including MoS2and WS2, are potential candidates for next-generation semiconducting materials owing to their atomically thin structure and strong optoelectrical responses, which allow for flexible optoelectronic applications. Monolayer TMDCs have been grown utilizing chemical vapor deposition (CVD) techniques. Enhancing the domain size with high crystallinity and forming heterostructures are important topics for practical applications. In this study, the size of monolayer WS2increased via the vapor–liquid–solid growth-based CVD technique utilizing the confined space of the substrate-stacked microreactor. The use of spin-coated metal salts (Na2WO4and Na2MoO4) and organosulfur vapor allowed us to precisely control the source supply and investigate the growth in a systematic manner. We obtained a relatively low activation energy for growth (1.02 eV), which is consistent with the surface diffusion-limited growth regime observed in the confined space. Through systematic photoluminescence (PL) analysis, we determined that a growth temperature of ∼820 °C is optimal for producing high-quality WS2with a narrow PL peak width (∼35 meV). By controlling the source balance of W and S, we obtained large-sized fully monolayered WS2(∼560 μm) and monolayer WS2with bilayer spots (∼1100 μm). Combining two distinct sources of transition metals, WS2/MoS2lateral heterostructures were successfully created. In electrical transport measurements, the monolayer WS2grown under optimal conditions has a high on-current (∼70 μA/μm), on/off ratio (∼5 × 108), and a field-effect mobility of ∼7 cm2/(V s). The field-effect transistor displayed an intrinsic photoresponse with wavelength selectivity that originated from the photoexcited carriers.