Prof. Sunkook Kim ((Department of Advanced Materials Science and Engineering) develops large area MoS₂ film for transparent phototransistor by plasma assisted chemical vapor deposition technique.

Professor Sunkook Kim’s research team (Department of Advanced Materials Science and Engineering) developed a route to synthesis low temperature plasma assisted large area MoS₂ film for transparent phototransistor. Transparent devices on low-cost glass substrate using transition metal dichalcogenides (TMDs), required additional mechanical transfer which induces wrinkles, voids, cracks on the channel and hinder the mass production. 

TMDs such as MoS₂ have attracted considerable attention or the fabrication of ultra-sensitive and ultrathin photodetectors because of their layer-dependent bandgap, optical transparency, high current on/off ratio, high carrier mobility, temperature stability, and large scalability. However, the synthesis of MoS₂ required high temperature (> 600 °C), therefore growth on an inexpensive transparent substrate with low thermal budgets is challenging. Numerous techniques have been proposed for obtaining MoS₂ at low temperature (< 400 °C) including MOCVD, ALD, PECVD etc. MOCVD required long sulfurization time for large area coverage, while ALD either required post annealing or produce rough film at low temperature. Few groups have used PECVD to grow large area MoS₂ film at low temperature, however poor quality of the film hinder their application in transistor. 

Research team of Professor Sunkook Kim (Arindam Bala, Liu Na and all the authors) have synthesis large area MoS₂ film on inexpensive slide glass (MARIENFELD.) by plasma assisted chemical vapor deposition technique (≤ 400 °C) and fabricated 7 × 7 array of transparent phototransistor without additional mechanical transfer, which can detect visible light (λ = 405 nm, 652 nm). 

Prof. Kim said, “This study is significant for developing low-cost smart glass technologies”.

This research was supported in part by the National Research Foundation of Korea. 

(No. 2021R1A2B5B02002167, 2020H1D3A2A02103378, 2020R1I1A1A01052893)

This work was supported by Institute of Information & communications Technology Planning & Evaluation (IITP) grant funded by the Korea government (MSIT) (No. 2021-0-01151) and published on 10^th August 2022 in Advanced Functional Materials (I.F.: 19.92). 

Paper name: Low-Temperature Plasma-Assisted Growth of Large-Area MoS₂ for Transparent Phototransistors.

DOI: https://doi.org/10.1002/adfm.202205106

Article by Bala Arindam