Atomic-level Insight and Quantum Chemistry of Ambient Reliability Issues of the TMDs Devices

Long-term ambient reliability issues of the TMDs devices, like hysteresis behavior, are serious challenges to be addressed for its robust application. The root cause of the problem and the hypothesis presented earlier has not been inspected at the atomic level yet. This work presents the atomic-level insight into the vacancy-assisted interaction of TMDs with various ambient gases and its implications on the I-V hysteresis under different atmospheric, bias, and temperature conditions. The work reveals that introducing distinct donor and acceptor states is attributed to the adsorption of different atmospheric adsorbates over chalcogen defect sites in TMDs and their orbital interaction. The positive gate field ionizes donor states, resulting in a positive drain current shift (anticlockwise hysteresis loop), whereas the negative gate field ionizes acceptor states, leading to carrier recombination. The recombination phenomena are validated by demonstrating recovery of drain current shift when a strong negative gate bias was applied. The atomistic insights developed corroborates very well with the experimental observations.