High-performance nonvolatile organic transistor memory devices using the electrets of semiconducting blends

Area of Science:

• Materials Science
• Organic Electronics
• Semiconductor Devices

Background:

• Organic nonvolatile transistor memory devices are crucial for next-generation electronics.
• Tuning memory characteristics requires precise control over semiconductor and electret materials.
• Understanding charge storage and transfer mechanisms is key to device optimization.

Purpose of the Study:

• To investigate the impact of different electret materials on the performance of organic nonvolatile transistor memory devices.
• To explore the relationship between electret composition, energy barriers, and memory characteristics (WORM vs. flash).
• To enhance the operational stability and cycle endurance of these memory devices.

Main Methods:

• Fabrication of organic nonvolatile transistor memory devices using N,N'-bis(2-phenylethyl)-perylene-3,4:9,10-tetracarboxylic diimide (BPE-PTCDI) as the n-type semiconductor.
• Utilization of various electret materials, including poly[4-(diphenylamino)benzyl methacrylate] (N(PTPMA)3) and its blends with PCBM, TIPS-pen, or ferrocene.
• Analysis of memory characteristics (WORM, flash, retention, cycle endurance) under different electret configurations and gate bias conditions.
• Insertion of a poly(methacrylic acid) (PMAA) layer to further improve device performance.

Main Results:

• The PCBM:N(PTPMA)3 blend electret demonstrated a transition from WORM to flash memory with increasing PCBM content, enabling repeatable operation via tunneling.
• Donor/donor electrets like TIPS-pen:N(PTPMA)3 and ferrocene:N(PTPMA)3 resulted in flash and WORM characteristics, respectively, attributed to interfacial energy barrier differences.
• All devices exhibited long data retention (>10(4) s) and stable read-out currents.
• Incorporating a PMAA layer significantly enhanced the write-read-erase-read (WRER) cycle endurance to 200 times.

Conclusions:

• The energy level and charge transfer dynamics within blend electrets significantly influence and allow tuning of nonvolatile transistor memory device characteristics.
• Interfacial energy barriers play a critical role in determining the memory behavior (WORM vs. flash).
• The strategic use of electret materials and layered structures offers a promising pathway for developing high-performance organic memory devices.