SEMINAR

Atomically thin 3D semiconductors

 

Jong-Hoon Kang

 

Department of Materials Science and Engineering, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea​

 

3D architecture design and process with thin and lightweight components is promising for high-speed and low-power operation towards next generation electronics and optoelectronics. However, constructing 3D nanoscale structures from atomically thin semiconductors is challenging. Here, we present a unique approach to demonstrate three-dimensional (3D) nano-structuring of atomically thin semiconductors using transition metal dichalcogenides (TMDs). For this, the conformal growth of monolayer TMDs (MoS₂, WS₂, and WSe₂) has been optimized on surfaces with nanoscale half-spherical textures, producing wafer-scale optical films with distinct geometry at different length scales. Using this approach, we successfully reprogram their optical properties to produce atomically thin TMD films that are optically isotropic. Our films show optical flatness and uniformity at the macroscale, conformal and continuous films at the mesoscale, and atomic lattice configuration of monolayer TMDs at the microscale. The resulting films show an order-of-magnitude increase in the out-of-plane susceptibility for enhanced angular performance, compared to their flat-film counterparts. We further show that such 3D geometric programming of optical properties is applicable to different TMD materials, offering spectral generalization over the entire visible range.