DFT Study of ALD Nucleation of Sub-nanometer Scale Dielectric Formation on TiOPc/Graphene for Low Power Electronics Beyond CMOS
Pabitra Choudhury±, Jun Hong. Park† and Andrew C. Kummel‡.
±Department of Chemical Engineering, New Mexico Tech, Socorro, NM
†Materials Science & Engineering Program, University of California, San Diego, CA
‡Departments of Chemistry & Biochemistry, University of California, San Diego, CA
High performance tunneling Field Effect Transistors (TFET) will enable next generation terahertz detectors and new RF systems, but their realization at the nano-scale with high operation frequency has been a challenge because the processing of III-V materials is not only incompatible with Si CMOS technology causing high power consumption but also the cost is very high. So, beyond-CMOS devices, such as MOSFET devices based on 2D semiconductor heterostuctures could be used to address some of the above mentioned challenges. Graphene, an atomically-thin layer of carbon atoms, has opened many opportunities in the field of electronics due to its tunable enhanced electronic transport properties. Moreover, graphene based 2D materials can provide ballistic transport of charge carriers as well as carrier confinement, can lead to reduce power consumption, which are essentially attractive features for future electronic devices. These devices require deposition of thin dielectrics between two semiconducting layers. It is however possible to overcome this difficulty via ALD process. These materials have been made from functionalized graphene. Initially, graphene was functionalized with ordered monolayer and/or multi-layers of titanyl phthalocyanines (TiOPc) via ALD process, and then the functionalized graphene was utilized to make a Graphene/MPc/insulator sandwich, which is the essential key materials for low power electronic devices. We have used combined density functional theory (DFT) calculations and experimental approach to develop this material. Our calculations show that upon deposition of MPc mono-/bi-layer on graphene surface does not perturb the Dirac cone. This could led us to design beyond CMOS electronic devices which need to have ballistic charge transport characteristics, which will essentially have very important applications to design low power future electronic devices, will also be discussed.
DFT calculation work was also supported from NSF TeraGrid (XSEDE) resources under allocation number [TG-DMR140131]. Use of the Center for Nanoscale Materials was supported by the US Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.