High‐Performance Organic Field‐Effect Transistor with Matching Energy‐Band Alignment between Organic Semiconductor and the Charge‐Trapping Dielectric

Abstract

speed, serious retention degradation, and instability in air still should be overcome for the charge-trap OFETs. [10][11][12] The charge-trap OFET derives from the complementary metal-oxide semiconductor silicon-oxide-nitride-oxide-silicon (SONOS) memory, which is nowadays the most viable solution to replace the current floating gate-based technology and to scale the Flash NAND memories beyond the 16 nm node, [13] although its working mechanism including the carrier transportation in organic semiconductor and the transfer characteristics of OFET is not completely consistent with that of SONOS memory. Recently, much efforts have been made to achieve high performance Si-based chargetrap memory (CTM) devices through matching the energy-band alignments between Si and the charge-trapping dielectric. [14][15][16] It was found that at an applied electric field, the lower difference between the conduction-band minimum of Si and the charge-trapping dielectrics leads to a larger memory window, a higher programming/erasing speed and a better retention characteristics for the CTM devices. So theoretically a nonvolatile charge-trap OFET with matching alignment between the energy band of the charge-trapping dielectric and the corresponding molecular orbitals of organic semiconductor should also get an enhanced performance.ZnTe is an II/VI semiconductor, and the conduction band minimum and the valence band maximum have matching High-performance bottom-gate nonvolatile organic field-effect transistor (OFET) devices based on a special matching energy-band alignment between the organic semiconductor pentacene and the charge-trapping dielectric ZnTe are reported. The lower potential difference between the conduction band minimum of ZnTe and the lowest unoccupied molecular orbital of pentacene with a weak electron conductivity endows the OFET a memory window of 10 V at an applied sweeping gate-voltage of ±15 V, a high I ON /I OFF ratio of more than 10 6 , and good retention with a high I ON /I OFF ratio of 6 × 10 5 after 10 4 s. The large memory window of the OFET is attributed to the unique energy-band alignment of the memory device and the high density of traps in Te-deficient ZnTe film, and the prominent retention is attributed to the deeply trapped electrons in the potential well formed by Al 2 O 3 tunneling and blocking layers.

Photoerasable Organic Field-Effect Transistor Memory Based on a One-Step Solution-Processed Hybrid Floating Gate Layer

“…Organic field-effect transistor (OFET) memories have attracted considerable attention due to the advantages, including low cost, light weight, easy processing, large area, and good compatibility with flexible substrates, so they have extensive prospects of applications ranging from sensors, flexible displays, to wearable electronic devices. − Because a floating gate is inserted between the channel and the substrate, the carriers can be trapped and maintained for a long time in the floating gate using only electrical stress, making the devices nonvolatile OFET memories. , Over the past two decades, those memories have been made great progress in performances, such as memory window, retention, endurance, and programming/erasing speed. − Beyond electrical operation, recently, nonvolatile OFET memories have also be tuned by light impetus when photoresponsive materials were used as active layers or floating gates, which is called optical memories. − …”

“…4,14 Additionally, this solution method meets the requirements of large area and flexible storage media in the future. 14 In this work, we report a simple approach to develop a nonvolatile photoerasable OFET memory using one-step solution-processed [6,6]-phenyl-C 61 -butyric acid methyl ester (PCBM)/PMMA composites as a photosensitive hybrid floating gate layer. PCBM was chosen as the charge-trapping medium due to its excellent charge-storage properties in memories and widespread application in photoelectric devices such as photodetectors, solar cells, and memories.…”

Ruddlesden–Popper‐Phase Hybrid Halide Perovskite/Small‐Molecule Organic Blend Memory Transistors

“…Evidently, the (PEA) 2 PbBr 4 /C 8 -BTBT transistors yield a ΔV M /V OP of ≈0.9, which is the highest reported value to date for organic TFTs. [47][48][49][50][51][52][53][54][55][56] To evaluate the suitability of Blend-II transistors as a practical non-volatile memory device, we studied the endurance and data retention characteristics at room temperature. Figure 5d displays the endurance results for a device subjected to 10 000 repeated programming cycles (write, read, and erase steps) using the gate voltage waveform shown in the inset.…”

High performance nonvolatile organic field‐effect transistor memory devices based on pyrene diimide derivative

“…Organic electronic devices, such as organic field‐effect transistors (OFETs), 1 organic solar cells (OSCs), 2,3 and organic memory devices (OMs) 4,5 have attracted great attention due to their advantages of low cost fabrication, light weight, and flexibility. Among them, organic memristor, 6 especially the non‐volatile memory device based on the OFET structure (OFET‐NVM), 7 is considered new generation of portable high‐density storage devices for future organic integrated circuits and portable electronic devices 8 . Considerable efforts have been devoted to improve the parameters of OFET‐NVMs, including the memory window, on/off ratio, programming/erasing voltage, switching speed, retention time, and endurance capability 9 .…”