ECE Seminar - Two-Dimensional Layered Materials Toward Scalable Controlled Hierarchical Phase/Structure-Engineered Hybrid Films Toward Functional Devices
Abstract:
Novel condensed matter systems can be understood as new compositions of elements or old materials in new forms. According to the definition, various new condensed matter systems have been developed or are under development in recent years. 2D layered materials, including graphene and transition metal dichalcogenides (TMDs) allow the scaling down to atomically thin thicknesses and possess unique physical properties under dimensionality confinement. The chemical vapor deposition (CVD) process is the most popular approach for all kinds of 2D materials due to its high yield and quality. In my first part of talk, an inductively coupled plasma (ICP) was used to synthesize Transition Metal Dichalcogenides (TMDs) through a plasma-assisted selenization process of metal oxide (MOx) at a low temperature. Compared to other CVD processes, ICP facilitates the decomposition of the precursors at lower temperatures. We create the phase/structure-engineered-1T/2H 3D-hierarchical 2D materials derived from the MOx 3D-hierarchical nanostructures through a low-temperature plasma-assisted selenization process with controlled shapes grown by a glancing angle deposition system (GLAD). The applications, including (1) water splitting, (2) gas sensors, (3) batteries, and (4) resistive change memory, will be reported. In addition, I would like to introduce the growth of high quality of 2D materials for the channel materials in my group. Furthermore, we also demonstrated the all-transferred MoS2-based transistor arrays combing the selectively transferred MoS2 film as the channel material and the transferred Au thin films as the contact electrode, yielding uniform electrical properties with carrier mobility of 10.45 cm2V-1s-1, SS of 203.94 mV/dec, normalized Ion of 8.3 μA/μm, and on/off ratio of 105, respectively.
Keywords: Two-Dimensional Layered Materials, glancing angle deposition system (GLAD)
The research activities of his lab are highly interdisciplinary and are committed to exploring new unpredicted levels of functional materials to enable new schemes on manipulating and processing of engineering nanomaterials in nanoelectronics and energy harvesting applications. He is committed to currently realize intellectual visions through studies on four major areas toward New Material Technologies: (1) Development of Cu(In, Ga)Se2 solar cell and its investigation on light-harvesting behaviors, (2) Development of various method to synthesize different Graphene/two-dimensional materials, (3) Low power resistive random access memory and (4) Growth of low dimensional materials and its possible functional application.