Organic devices promise to revolutionize the extent of, and access to, electronics by providing extremely inexpensive, lightweight and capable ubiquitous components that are printed onto plastic, glass or metal foils. One key component of an electronic circuit that has thus far received surprisingly little attention is an organic electronic memory. Here we report an architecture for a write-once read-many-times (WORM) memory, based on the hybrid integration of an electrochromic polymer with a thin-film silicon diode deposited onto a flexible metal foil substrate. WORM memories are desirable for ultralow-cost permanent storage of digital images, eliminating the need for slow, bulky and expensive mechanical drives used in conventional magnetic and optical memories. Our results indicate that the hybrid organic/inorganic memory device is a reliable means for achieving rapid, large-scale archival data storage. The WORM memory pixel exploits a mechanism of current-controlled, thermally activated un-doping of a two-component electrochromic conducting polymer.

We demonstrate a nonvolatile, write-once-read-many-times ͑WORM͒ memory device employing a hybrid organic/inorganic semiconductor architecture consisting of thin film p-i-n silicon diode on a stainless steel substrate integrated in series with a conductive polymer fuse. The nonlinearity of the silicon diodes enables a passive matrix memory architecture, while the conductive polyethylenedioxythiophene:polystyrene sulfonic acid polymer serves as a reliable switch with fuse-like behavior for data storage. The polymer can be switched at ϳ2 s, resulting in a permanent decrease of conductivity of the memory pixel by up to a factor of 10 3 . The switching mechanism is primarily due to a current and thermally dependent redox reaction in the polymer, limited by the double injection of both holes and electrons. The switched device performance does not degrade after many thousand read cycles in ambient at room temperature. Our results suggest that low cost, organic/inorganic WORM memories are feasible for light weight, high density, robust, and fast archival storage applications.

Abstract— The manufacture of large‐area arrays of thin‐film transistors on polymer substrates using roll‐to‐roll (R2R) processes exclusively is being developed. Self‐aligned imprint lithography (SAIL) enables the patterning and alignment of submicron‐sized features on meter‐scaled flexible substrates in the R2R environment. SAIL solves the problem of precision interlayer registry on a moving web by encoding all the geometry information required for the entire patterning steps into a monolithic three‐dimensional imprint with discrete thickness modulation. The pre‐aligned multiple‐step mask structure maintains its alignment regardless of subsequent substrate distortion. Challenges are encountered in relation to the novel nature of using flexible substrates and building toolsets for the R2R processing. In this paper, methods of the SAIL process, the resulting active‐matrix backplanes, the trajectory of SAIL process development, and the remaining issues for production are presented.

High-performance thin-film silicon n–i–p diodes are fabricated at temperatures below 160°C using hot-wire chemical vapor deposition. The 0.01mm2 diodes have a forward current-density of near 1000A∕cm2 and a rectification ratio over 107 at ±2V. Use of microcrystalline silicon i and n layers results in higher current-density diodes than with amorphous silicon, primarily by lowering a barrier to carrier injection. A 30nm intrinsic Si buffer layer between the i and p layers is needed to reduce the reverse leakage current. Minimizing diode area increases forward current density by reducing the voltage drop across the external series resistances.

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