News / In Focus

Chia-Hao Chen, Chung-Lin Wu, Semiconductor, monolayer diode, WSe2
MOST Press Conference – Breakthrough Material Research Brings Smaller and Faster Semiconductors
The press conference held by MOST on November 21st: (left to right) Director General Minn-Tsong Lin (Dept. of Natural Sciences and Sustainable Development, MOST), Dr. Chia-Hao Chen (NSRRC), Deputy Director Yu-Han Tsou (MOST), Prof. Chung-Lin Wu (NCKU) and Dr. Jhih-Wei Chen (NCKU).

       A collaborative research project led by NSRRC user, Prof. Chung-Lin Wu (Physics Department, National Cheng Kung University) and NSRRC scientist, Dr. Chia-Hao Chen, used WSe2 to successfully develop a monolayer diode at room temperature. It is only 0.7 nanometer thick and has the potential to move beyond Moore's Law* and achieve the next generation of energy-saving integrated circuits (ICs). The Ministry of Science and Technology (MOST) held a press conference on November 21st to highlight this research, which was published in Nature Communications.

       The properties of 2D materials will help develop novel devices across a number of semiconductor-related applications, such as biosensors, energy storage, and photovoltaic cells. The team produced a non-volatile lateral pn diode by integrating a monolayer WSe2 on a multiferroic BiFeO3 substrate, for high-performance rectifying required for core logic applications. Compared to common silicon semiconductors, where transistor channel size has hit a hard limit of 3 nm, the monolayer diode is thinner, smaller and faster. In addition, it reduces the complexity in IC design and processes, electricity leakage, and circuit shortage. Future applications like artificial intelligence chipsets and machine learning for self-driving cars that require high performance computing and energy efficiency would possibly benefit from such a monolayer diode.

       To directly visualize the electronic structure of WSe2 on BiFeO3, the team used a scanning photoelectron microscope and spectroscopy (SPEM/S) at TLS beamline 09A1. The SPEM endstation provides the required energy, spatial resolution and surface sensitivity for the study of the ultra-thin 2D material systems.

*Moore's Law is the observation formulated by Intel co-founder Gordon Moore in 1965 that the number of transistors per square inch on integrated circuits doubles about every two years. It has served as a guiding principle in the technology industry.