Low-dimensional Electron Systems Lab

High mobility transistors, steep-slope transistors, low-power tunneling electronics, multi-valued logics, electronic sensors, contact property optimization etc. We are interested in various quantum phenomena such as quantum Hall effect and topological/quantum spin Hall states in two-dimensional materials. In such nanoscale materials due to the reduced dimensionality quantum effect can be pronounced. Using our non-local Fermi energy measurement technique we are capable of direct probing of energy of such quantum states. We design novel condensed matter systems, study new quantum phenomena, and explore practical nanoelectronics using emerging nanoscale materials and physics. This research includes developing new method of nano fabrication and precise characterization techniques. 2D materials show great promise as potential replacements for silicon, primarily because they do not suffer from performance degradation caused by miniaturization. Nevertheless, the broader implementation of 2D semiconductors faces certain challenges, such as high contact resistance and Fermi level pinning issues. These limitations pose obstacles to the practical utilization of 2D semiconductors in various fields, particularly in the development of CMOS circuits and systems because p-type 2D semiconductor options are highly restricted. We have recently achieved realization of ambipolar characteristics of 2D MoS2 and InSe by developing advanced van der Waals contacts that relieve the Fermi-level pinning without forming defects at the surface of semiconductors. This allowed us to invent unprecedented strategies to achieve superior ambipolar characteristics and complementary reconfigurable multifunctionality. We also aim to demonstrate circuits composed of such reconfigurable devices and validate the