Memory effect and RF switch applications based on two-dimensional materials

Since Novoselov and Geim rediscovered the promising characteristics of single-layer graphene at 2004, various two-dimensional (2D) materials such as graphene, transition-metal dichalcogenides (TMDs), hexagonal boron nitride (hBN), Xenes (silicene, phosphorene, germanene) gained a lot of interest due to their unique and fascinating physical properties. Recently, these novel semiconducting 2D materials have led to a variety of promising technologies for nanoelectronics, photonics, sensing, energy storage, and optoelectronics, to name a few. In this dissertation, we report a detailed study of memory effect and RF switch applications based on two-dimensional materials. In chapter 2, we report non-volatile resistive switching (NVRS) in single-layer atomic sheets sandwiched between metal electrodes. We named this device as Atomristor and it shows low switching voltage, forming-free characteristic, high on/off ratio, and record pulse operation. Ab-initio simulations reveal that the NVRS can be attributed to the interactions between metal ions and sulfur vacancies. In chapter 3, RF switches based on the forming-free MoS2 non-volatile memory are discussed to overcome the limitations of conventional emerging RF switch technologies. The MoS2 switches have low insertion loss and high isolation, scalable cutoff frequencies, and displays good linearity. In chapter 4, analog switches made from boron nitride monolayers for application in 5G and terahertz communication systems are examined. The hBN switches achieve a better insertion loss, isolation, and power handling compared to MoS2 RF switches. For data communication systems, eye-diagram and BER measurements were conducted to evaluate the distortion and revealed a good operation at a bit rate of 8.5 Gbit s-1. In chapter 5, single-pole-double-throw (SPDT) RF switches based on 2D memristors are explored for practical circuit applications.