Xiuling Li

University of Illinois

(moving to University of Texas, Austin in Sept. 2021)

 

From lasers to transistors, semiconductor heterojunctions have played essential roles in enabling carrier transport, confinement, signal switching and amplification. The holy grail of semiconductor heterojunctions is to place any two different materials on top of each other monolithically without forming any interfacial defects or experience any undesirable strain. For traditional semiconductor materials, the formation of heterojunctions is naturally limited by the lattice and thermal matching. 2D TMDC materials have presented an unpresented paradigm for heterojunction formation because of their interlayer van der Waals bonding nature. van der Waals (vdW) epitaxy completely relaxes the lattice and thermal matching related strain restriction and creates heterojunctions with new kinds of band alignments that are otherwise impossible. The heterojunction interface quality defines the device function and performance. Direct growth of 2D material on conventional 3D semiconducting materials and vice versa, especially epitaxially, has substantial potential for high performance heterojunction devices. In this talk, I will present examples of 2D/3D heterojunction growth and discuss the role of lattice matching on vdW epitaxy and implications on ultra-scaled semiconductor devices.