CAREER: Two-Dimensional Straintronic Field Effect Transistor

Proposal Number: 2042154 Principal Investigator: Saptarshi Das Title: CAREER: Two-Dimensional Straintronic Field Effect Transistor Institution: Pennsylvania State Univ University Park Nontechnical Abstract: Energy efficient computing will revolutionize next generations of smart and secure electronic devices, and benefit all sectors of modern society including agriculture, healthcare, automation, communication, defense, and infrastructure. In fact, the 21st century, which promises to thrive on big data, remote sensing, Internet-of-Things (IoT) and so on, demands novel devices, which can operate with power so frugal that ambient energy harvesting may accommodate all of their needs. The conventional silicon based complementary metal oxide semiconductor technology is inadequate for achieving such goals necessitating novel material discovery and device level innovations. This may be achieved in two-dimensional straintronic field effect transistors by utilizing a unique property of two-dimensional materials, namely, strain induced dynamic bandgap engineering and integrating it with piezoelectric nanotransducers, which will be explored in the proposed research. Technical Abstract The aim of the proposal is to experimentally demonstrate steep slope switching in two-dimensional straintronic field effect transistors (2D SFET) exploiting in-operando and uniaxial strain engineering in 2D transition metal dichalcogenides (TMDCs). The 2D SFET can defy the thermodynamic limit imposed by Boltzmann statistics in conventional metal oxide semiconductor field effect transistors (FET) and achieve sub-60mV/decade subthreshold swing at room temperature along with high on-state performance. Realization of 2D SFET requires monolithic integration of 2D TMDC based FETs with piezoelectric (PE) ceramic based nanotransducers. The PE expands in response to an applied gate bias and transduces an out-of-plane stress on the 2D channel material reducing its bandgap. The result is an internal voltage amplification that leads to steep slope switching. While static, in-plane, and biaxial strain is used in conventional silicon technology, dynamic strain engineering is a relatively uncharted territory. Consequently, exploration of novel straintronic devices based on novel 2D TMDCs will add new fundamental knowledge towards advancing concepts for resolving critical computing needs and grand engineering challenges. Furthermore, the proposed straintronic platform will offer exciting opportunities to develop novel concepts including straintronic neuromorphic devices (SNDs) for brain-inspired computing, straintronic memory devices (SMDs) for in-memory computing, and straintronic security devices (SSDs) for secure computing. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.