Solution processed molecular floating gate for flexible flash memories

Abstract

Solution processed fullerene (C60) molecular floating gate layer has been employed in low voltage nonvolatile memory device on flexible substrates. We systematically studied the charge trapping mechanism of the fullerene floating gate for both p-type pentacene and n-type copper hexadecafluorophthalocyanine (F16CuPc) semiconductor in a transistor based flash memory architecture. The devices based on pentacene as semiconductor exhibited both hole and electron trapping ability, whereas devices with F16CuPc trapped electrons alone due to abundant electron density. All the devices exhibited large memory window, long charge retention time, good endurance property and excellent flexibility. The obtained results have great potential for application in large area flexible electronic devices.

Organic Transistor Memory with a Charge Storage Molecular Double-Floating-Gate Monolayer

“…That ND can trap hole carriers is more or less unexpected, even though holes and electrons were reported to be trapped in the electronaccepting molecules such as C60 when they were embedded into a pentacene-based transistor. 33 Nevertheless, as can be seen later, the ND system cannot seem to stabilize the hole carriers well enough so that the positive charges are lost fast. In the system with both DA and ND moieties incorporated, the V th can shift in either direction, depending on the original pulse, presumably for the same reasons cited above.…”

Phthalocyanine‐Cored Star‐Shaped Polystyrene for Nano Floating Gate in Nonvolatile Organic Transistor Memory Device

“…This result indicates that the limited number of hole charges are trapped in the CuPc-PS 4 gate vias. [ 20,21,42 ] The maximum memory I ON / I OFF ratio between programmed and erased states was over 10 7 owing to the large intrinsic I ON / I OFF ratio of the CuPc-PS 4 -embedded OFET device, which led to greater ease in distinguishing the information storage levels. Moreover, the 1st (Sweep 1) and 2nd (Sweep 3) programming processes resulted in almost identical transfer curves upon applying negative pulses, which indicated that the programming/erasing cycle was suffi ciently repeatable to be categorized as a fl ash-type memory device.…”

“…The versatility of the chemical structure of the Pc-cored star polymer would provide large advantages in fabricating and optimizing electronic devices for various applications such as next generation fl exible memory devices. [40][41][42] Herein, the preparations, characterizations, and electrical properties of star-shaped CuPc-PS 4 were systematically explored. Star-shaped polystyrene without a CuPc core, PS 4 , was also investigated for comparison.…”

Stable organic static random access memory from a roll-to-roll compatible vacuum evaporation process

“…Not surprisingly, then, many different types of organic memory devices have also been reported e.g. switchable resistive memory [11,12], floating gate memory devices [13] and memory transistors [14]. Also reported are organic versions of dynamic [15] and static [16][17][18][19] random access memory i.e.…”