2, Vanderbilt University, Nashville, Tennessee, United States
3, University of Georgia, Athens, Georgia, United States
The voltage controlled charge-density-wave (CDW) phase transition in quasi-2D 1T-TaS2 offers a possibility of using the switching behavior of these macroscopic quantum states for electronic applications. We have recently demonstrated a frequency tunable oscillator based on an integrated graphene–h-BN–TaS2 device that is capable of operating at room temperature . The carrier concentrations in the nearly commensurate (NC) and incommensurate (IC) CDW phases in 1T-TaS2, which are utilized for switching the device, are very high, on the order of 1021 cm-3 and 1022 cm-3, respectively. The high carrier concertation creates conditions for resilience to the total ionizing dose (TID) effect, which is radiation damage to semiconductor device in space and high-energy accelerator environment. In conventional MOSFET, electron–hole pairs generated in the oxide during TID irradiation can accumulate in the oxide layers and interfaces, leading to the shifts in the threshold voltage and increase in the leakage current. Unlike conventional field-effect-transistors (FETs), the 1T-TaS2 device is a two-terminal CDW device, in which the switching is controlled by the source-drain voltage rather than the gate voltage. No gate oxide is needed for its operation . In this work, we evaluate the TID response of 1T-TaS2 CDW devices by examining the current-voltage (I-V) characteristics under X-ray irradiation at doses up to 1 Mrad(SiO2). We find that the threshold voltage, VTH, for the abrupt resistance change shifts by only ~2%, the resistance of the CDW states changes by less than ~2 % (low resistive state) and ~6.5 % (high resistive state), and the self-sustained voltage oscillations in this 1T-TaS2 oscillator function well after the full irradiation sequence . The obtain results indicate that 1T-TaS2 CDW devices are promising for applications in space and other high-radiation environments.
The work at UC Riverside was supported, in part, by NSF EFRI 2-DARE project: Novel Switching Phenomena in Atomic MX2 Heterostructures for Multifunctional Applications and by UC-National Lab Collaborative Research and Training Program.
 G. Liu, B. Debnath, T. R. Pope, R. K. Lake, T. T. Salguero and A. A. Balandin, Nature Nanotechnology, 11, 845 (2016).
 G. Liu, E. X. Zhang, C. D. Liang, M. A. Bloodgood, T. T. Salguero, D. M. Fleetwood, A. A. Balandin, IEEE Electron Device Letters (accepted, 2017) 10.1109/LED.2017.2763597.