A Study Of Nanoelectronic Devices And Gate-contrlled Behaviours Based On Atomically Thin MoS₂

In 1959,physicist Richard Feynman raised a question in his famous lecture,"There’s plenty of room at the bottom.":"What could we do with layered structures with just the right layers?" With the discovery of two-dimensional layered materials(2DMLs),we are getting closer and closer to answer that question.Nowadays,reseachers can make various functional van der Waals heterostructures(vdWHs)through artificial nanocomposite and develope all kinds of novel physical performance which make vdWHs devices hold great promise for next generation nanoelectronics.Molybdenum disulfide(MoS2)has received lots of attentions because of its suitable band gap and unique features in 2DMLs.This thesis presents the field effect transistors with special performance and their transport characterizations based on MoS2.The main results are shown as follows:Based on traditional dry transfer technique,we developed a new way of so-called reverted transfer to make ultrathin 2DML as the most top layer of vdWHs.We can get rid of the limits of thickness,variety,and size by using this mothed,and obtain vdWHs as needed rapidly and efficiency.Meanwhile,no contamination,bubbles or wrinkles appear on the surface of ultrathin 2DML during the transfer.This method opens new routes to the high cleanliness requiring devices,such as scanning tunnelling microscope on pristine 2D materials supported by another,as well as the high quality spacing layer for tunnelling electrodes.We fabricated few layer MoS2 tunnelling field effect transistors(TC-FETs)with ultrathin h-BN as tunneling layer using the reverted transfer mothed.The existence of ultrathin h-BN makes it possible to suppress the Schottky barriers and Fermi level pinning,leading to homogeneous gate-control of the channel chemical potential across the bandgap edges.It is found that the MoS2 TC-FETs will present ambipolar while the source-drain voltage is a finite positive value.The device also has gate-controlled reversible rectifying behaviour,that is,the device can display pn diode,off,np diode and full-pass four multiple working states when the device was controlled by gate voltage.This novel result paves the way for future logic applications and high performance switches based on atomically thin semiconducting channel.Fabricating MoS2 FETs devices using PZT ferroelectric film as bottom gate voltage.We primarily studied the electrical transport of device and found that the device is a very fresh two-level transistor when applied navigates voltage,threshold swing is 125 mV/dec.We observed an anti-hysteresis response in device which was resulted from trapping charge,and its possible to solve this problem by inseting a buffer layer,therefore obtain high quality,and ultralow threshold swing.