First Demonstration of Fundamental Transistor Operation on a Directly Grown 2D Semiconductor Wafer: Paving the Way Toward Integrated Circuit Platforms Without Transfer Processes

The research team has identified the cause of degraded transistor performance in single-crystal MoS₂ grown on sapphire substrates by metal-organic chemical vapor deposition (MOCVD). They found that the poor switching behavior—specifically, the inability to achieve a clear on/off current modulation—originates from “hidden electron doping” caused by sulfate groups and water-related species remaining at the MoS₂/sapphire interface.

To address this issue, the team developed a fully dry interface engineering process in which a hydrogen/argon (H₂/Ar) annealing step is applied after device fabrication and patterning. This treatment effectively removes interfacial impurities through the atomic-layer gaps of MoS₂. As a result, they demonstrated, for the first time, excellent transistor operation directly on the as-grown wafer without requiring a transfer process to another substrate, which had previously been considered essential.

This achievement eliminates the need for the transfer process, one of the biggest bottlenecks in 2D semiconductor technology due to the difficulty of maintaining a clean interface. The work opens a pathway toward directly utilizing high-quality single-crystal MoS₂ grown on sapphire as a wafer platform for electronic devices. It represents an important milestone toward the project’s strategic goal of establishing fundamental technologies for the use of low-dimensional materials in next-generation semiconductor device architectures. The technology is expected to accelerate the development of AI semiconductors and future low-power logic devices, which are key priorities for Japan’s semiconductor strategy.

MoS₂ wafer devices directly formed on a sapphire substrate and their excellent on/off switching characteristics (channel length L = 20 μm, channel width W = 10 μm). By employing interface engineering alone, without any transfer process, the researchers achieved high-performance transistor operation. Red and black curves represent the device characteristics before and after H₂/Ar annealing, respectively.

Papers

Journal: Advanced Materials

Title: MOCVD-Grown MoS₂ Wafers as a Transfer-Free Platform for Top-Gate Devices via Dry Interface Engineering

Authors: Shuhong Li, Juiteng Chang, Keisuke Atsumi, Kosei Matsumoto, Itsuki Tanaka, Tomonori Nishimura, Kaito Kanahashi, Takahiro Nagata, Jun Nara, Yoshiki Sakuma, Emi Kano, Nobuyuki Ikarashi, and Kosuke Nagashio*

DOI: 10.1002/adma.73931