Charge trapping over the channel can occur from program/erase cycling of Flash memory cells, increasing the cell threshold voltage and causing threshold shifts in retention tests when charges detrap. The empirical characteristics of these effects are discussed. Trapping has a square-root dependence on program/erase cycle count. Detrapping scales with the logarithm of time and is thermally accelerated with an activation energy of 1.1 to 1.2 eV. Detrapping has only a weak dependence on electric field. These mechanisms are intrinsic, yet there is a wide variation in behavior from one cell to another related to Poisson statistical variations. Common reliability characterization methods need to be re-thought in light of the characteristics of this and other mechanisms. In particular, performing extensive program/erase cycling with no delays between cycles is unrealistic for this mechanism, and alternative distributed-cycling schemes are proposed.
Electronics allowing for visible light to pass through are attractive, where a key challenge is to make the core functional units transparent. Here, it is shown that transparent electronics can be constructed by epitaxial growth of metal–organic frameworks (MOFs) on single‐layer graphene (SLG) to give a desirable transparency of 95.7% to 550 nm visible light and an electrical conductivity of 4.0 × 104 S m−1. Through lattice and symmetry match, collective alignment of MOF pores and dense packing of MOFs vertically on SLG are achieved, as directly visualized by electron microscopy. These MOF‐on‐SLG constructs are capable of room‐temperature recognition of gas molecules at the ppb level with a linear range from 10 to 108 ppb, providing real‐time gas monitoring function in transparent electronics. The corresponding devices can be fabricated on flexible substrates with large size, 3 × 5 cm, and afford continuous folding for more than 200 times without losing conductivity or transparency.
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