Toward Chemoresistive Sensor Array Based on Two- dimensional Materials

Speaker: Dr. Ho Won Jang, Seoul National University

Introduction to the Speaker：

Dr. Jang received his Ph.D. at the Department of Materials Science and Engineering from the Pohang University of Science and Engineering (POSTECH) in 2004. From 2004 to 2005, he was a post-doc in the POSTECH. He developed the fabrication process of vertical GaN LEDs with reflective p-contacts on conducting substrates such as Ni using a laser lift-off process. From 2006 to 2009, he worked at the University of Wisconsin-Madison as a research associate. He had been in charge of synthesizing epitaxial perovskite oxide thin films for electronics. Dr. Jang was a senior research scientist of the Electronic Materials Center at the Korea Institute of Science and Technology (KIST), where he worked on the oxide nanostructures for gas sensors from 2009 to 2012. He joined the Department of Materials Science and Engineering of the Seoul National University in 2012. Dr. Jang has published more than 270 journal papers in the area of Materials Science. His research has focused on synthesis and applications of oxides, 2D materials, and halide perovskites for chemical sensors, solar water splitting, and nanoelectronics. He is serving as an editor for the journals, Electronic Materials Letters and Current Applied Physics, and an editorial board member for Scientific Reports and Applied Sciences.

Abstract：

Internet of things (IoT) is the network of physical objects or “things” embedded with electronics, software, and connectivity to enable it to achieve greater value and service by exchanging data with the manufacturer, operator and/or other connected devices. One of the key technologies of the IoT is sensors. Gas sensors that convert chemical information ranging from the concentration of a specific target component to total composition analysis into analytically useful signals have been widely used in broad fields. In order to fulfill needs for IoT, low power consumption, low cost, miniaturized size, and easiness to be integrated with electronic circuits along with high sensing performance are essential for gas sensors. Gas sensors based on nanostructured semiconducting metal oxides lead to high responses to various gases, but they operate with external heaters to maintain the materials at elevated temperatures. The use of a heater that operate high temperatures (> 300oC) not only increases the power consumption but also causes thermal stability problems, hindering practical applications. Here we present our methods to enhance gas sensing properties of 2-dimensional materials such as graphene, graphene oxide flakes, MoS2 thin films, and MoS2 nanoparticles. We show that surface functionalization and nano/microscale structural modification are the key in improving gas response and selectivity. We present our strategy to make sensor array using low-power-consumption operation of chemoresistive gas sensors based on functionalized graphene and transition metal disulfides.

Host：Prof. LU Geyu

Time：09:00, Jan. 7^th, 2020

Location：Room D314, Tang Aoqing Buliding