Diffusion Control on the Van der Waals Surface of Monolayers for Uniform Bi‐Layer MoS<sub>2</sub> Growth
Tae Soo Kim, Gichang Noh, Seongdae Kwon, Ji Yoon Kim, Ji Yoon Kim, Krishna P. Dhakal, Saeyoung Oh, Hyun‐Jun Chai, Eunpyo Park, In Soo Kim, Eunji Lee, Young‐Bum Kim, Jaehyun Lee, Min‐kyung Jo, Minsoo Kang, Cheolmin Park, Jeongho Kim, Jeongho Kim, Jeongwon Park, Suhyun Kim, Mingyu Kim, Yuseok Kim, Sung‐Yool Choi, Seungwoo Song, Hu Young Jeong, Jeongyong Kim, Jeongyong Kim, Joon Young Kwak, Kibum Kang
Abstract
Abstract 2D MoS 2 has gained attention for the post‐silicon material owing to its atomically thin nature and dangling bond‐free surface. The bi‐layer MoS 2 is considered a promising material for electronic devices due to its better electrical properties than monolayer MoS 2 . However, the uniform growth of bi‐layer MoS 2 is still challenging. Herein, the uniform growth of bi‐layer MoS 2 is demonstrated using gas‐phase alkali metal‐assisted metal–organic chemical vapor deposition (GAA‐MOCVD). Thanks to enhanced metal reactant diffusion length in GAA‐MOCVD, the uniform growth of bi‐layer MoS 2 film is achieved even at fast nucleation kinetics for a shorter growth time compared to previously reported MOCVD. The bi‐layer MoS 2 field‐effect transistors (FETs) show superior electrical properties such as sheet conductance and electron mobility than monolayer MoS 2 FETs. The electron mobility of bi‐layer MoS 2 FETs with bismuth contacts reaches a maximum of 92.35 cm 2 V −1 s −1 . Using the partially grown epitaxial bi‐layer (PGEB) MoS 2 , it is demonstrated that a photodetector showed a near‐infrared photoresponse with a low dark current that is advantageous for both monolayer and bi‐layer applications. The potential expansion of the growth technique to layer‐by‐layer growth can result in boosted performance across a wide spectrum of electronic and optoelectronic devices employing MoS 2 .