High Performance Transparent Transistor Memory Devices Using Nano-Floating Gate of Polymer/ZnO Nanocomposites.

Nano-floating gate memory devices (NFGM) using metal nanoparticles (NPs) covered with an insulating polymer have been considered as a promising electronic device for the next-generation nonvolatile organic memory applications NPs. However, the transparency of the device with metal NPs is restricted to 60~70% due to the light absorption in the visible region caused by the surface plasmon resonance effects of metal NPs. To address this issue, we demonstrate a novel NFGM using the blends of hole-trapping poly (9-(4-vinylphenyl) carbazole) (PVPK) and electron-trapping ZnO NPs as the charge storage element. The memory devices exhibited a remarkably programmable memory window up to 60 V during the program/erase operations, which was attributed to the trapping/detrapping of charge carriers in ZnO NPs/PVPK composite. Furthermore, the devices showed the long-term retention time (>10(5) s) and WRER test (>200 cycles), indicating excellent electrical reliability and stability. Additionally, the fabricated transistor memory devices exhibited a relatively high transparency of 90% at the wavelength of 500 nm based on the spray-coated PEDOT: PSS as electrode, suggesting high potential for transparent organic electronic memory devices.

Single-crystal C60 needle/CuPc nanoparticle double floating-gate for low-voltage organic transistors based non-volatile memory devices.

Low-voltage organic field-effect transistor memory devices exhibiting a wide memory window, low power consumption, acceptable retention, endurance properties, and tunable memory performance are fabricated. The performance is achieved by employing single-crystal C60 needles and copper phthalocyanine nanoparticles to produce an ambipolar (hole/electron) trapping effect in a double floating-gate architecture.

Nonvolatile organic thin film transistor memory devices based on hybrid nanocomposites of semiconducting polymers: gold nanoparticles.

We report the facile fabrication and characteristics of organic thin film transistor (OTFT)-based nonvolatile memory devices using the hybrid nanocomposites of semiconducting poly(9,9-dioctylfluorene-alt-bithiophene) (F8T2) and ligand-capped Au nanoparticles (NPs), thereby serving as a charge storage medium. Electrical bias sweep/excitation effectively modulates the current response of hybrid memory devices through the charge transfer between F8T2 channel and functionalized Au NPs trapping sites. The electrical performance of the hybrid memory devices can be effectively controlled though the loading concentrations (0-9 %) of Au NPs and organic thiolate ligands on Au NP surfaces with different carbon chain lengths (Au-L6, Au-L10, and Au-L18). The memory window induced by voltage sweep is considerably increased by the high content of Au NPs or short carbon chain on the ligand. The hybrid nanocomposite of F8T2:9% Au-L6 provides the OTFT memories with a memory window of ~41 V operated at ± 30 V and memory ratio of ~1 × 10(3) maintained for 1 × 10(4) s. The experimental results suggest that the hybrid materials of the functionalized Au NPs in F8T2 matrix have the potential applications for low voltage-driven high performance nonvolatile memory devices.

Improving the characteristics of an organic nano floating gate memory by a self-assembled monolayer.

We demonstrate a novel approach to improve the characteristics of the gold nanoparticle-based organic transistor memory devices by using self-assembled monolayers (SAM) with different functional groups as interfacial modifier. SAM-based interfacial engineering significantly improved the hysteresis, memory window, and on/off ratio of a nano floating gate memory (NFGM) at zero gate voltage. This NFGM showed a large memory window of up to 190 V and on/off current ratio of 10(5) during writing and erasing with an operation voltage of 100 V of gate bias in a short time, less than 1 s. Furthermore, the devices show excellent nonvolatile behavior for bistable switching. The ON and OFF state can be stably maintained for 10(3) s with an I(on)/I(off) current ratio of 10(6) for a pentafluorophenyl trimethoxysilane modified device. The results suggested the importance of SAM-modified interface for the memory performance of NFGMs.

Self-assembled monolayers induced inter-conversion of crystal structure by vertical to lateral growth of aluminium doped zinc oxide thin films.

In this communication, we demonstrate the inter-conversion of crystal structure of aluminium doped zinc oxide (AZO) thin films from highly (002) plane oriented vertical growth to (103) plane oriented lateral growth by adjusting the polarity of the self-assembled monolayers (SAMs) on glass substrates at room temperature.

Discriminate crystallinities of tin doped indium oxide films on self-assembled monolayers modified glass substrates.

Tin doped indium oxide (ITO) films have generated tremendous research interest and received widespread applications in optoelectronic devices due to a good combination of desired optical and electrical properties. Their electrical properties vary depending on the crystallinity of the film. A good quality ITO film should have low resistivity, which can be achieved with highly crystalline films deposited at very high temperature. Thus, film quality is sensitive to the deposition conditions. Generally, low-temperature deposition of ITO results in poor quality films due to amorphous growth. In this study, we have demonstrated that crystallinity of the ITO films can be improved even at room temperature (RT) using self-assembled monolayers (SAMs) modified glass substrates. The present study demonstrates that SAM with -SH terminal group is necessary for the high-quality ITO growth, while SAMs with other terminal groups (-NH(2) and -CH(3)) generate ITO films with moderate crystallinity. Various properties of such films were investigated using X-ray diffraction, X-ray photoelectron depth profile, four-point probe, and Hall measurements. It is confirmed from such measurements that ITO film deposited on -SH terminated SAM substrate has excellent crystallinity, conductivity, and optical transmission.