Heng-Tien Lin

Carrier Transport Mechanism in a Nanoparticle-Incorporated Organic Bistable Memory Device

In this letter, the conduction mechanism in nanoparticle-contained polymer memory was investigated experimentally and theoretically. The current-voltage characteristics showed that the device switches from an initial low-conductivity state to a high-conductivity state upon application of an external electric field at room temperature. The current transition exhibited a very narrow voltage range that causes an abrupt increase of current. A trap-filled space-charge-limited current model was proposed and supported by the experimental data to explain the transport mechanism in organic memory.

A New Nonvolatile Bistable Polymer-Nanoparticle Memory Device

In this letter, we demonstrate a new organic bistable nonvolatile memory device that is adopting polymer-chain-stabilized gold (Au) nanoparticles in a host polymer as a memory active layer. In this letter, the Au nanoparticles are well dispersed in the host polymer so as to enhance stability of memory devices. Current-voltage characteristics show that the device switches from an initial low-conductivity state to a high-conductivity state upon applying an external electric field at room temperature. This memory can be switched ON and OFF for over 150 times without an apparent performance degradation. In addition, the memory state can retain for over 36 000 s in air. This memory device is thus considered to be a suitable candidate for flexible electronics applications.

A UV-Erasable Stacked Diode-Switch Organic Nonvolatile Bistable Memory on Plastic Substrates

In this letter, we demonstrate a robust and stacked diode-switch organic nonvolatile bistable memory (DS-ONBM) using polymer-chain-stabilized gold nanoparticles on a plastic substrate in ambient air. The absorption spectrum of the gold nanoparticles shows ultraviolet (UV) absorption. Therefore, UV light is used to erase data in the DS-ONBM. The data in the memory can be retained for more than ten days in the air. The estimated retention time is nearly a year. This DS-ONBM is demonstrated to read, write, and retain the data and is reusable by UV-light illumination. Hence, the UV-erasable DS-ONBM is fully applicable in printed electronics such as RFID tags.

A 16-Byte Nonvolatile Bistable Polymer Memory Array on Plastic Substrates

We demonstrate a 16-byte addressable organic nonvolatile bistable memory array (ONBM) on the plastic substrate. The memory cell can be switched on and off over 1,000 times and the data can be retained for more than 3 days in the air. Our ONBM are stable during the application of compressive stress down to 5 mm in bending radius. After connecting the ONBM array to the current-sensing circuit, the ONBM array can be correctly addressed and operated, while maintaining low-power consumption.

The temperature-dependent physical and electrical characteristics of a polymer/RAFT-polymer stabilized nanoparticle system for organic nonvolatile memory

We have fabricated and investigated organic memory diodes, comprising a single polymer layer and Au nanoparticles stabilized by the same polymer material utilizing a reversible addition-fragmentation transfer technique to suppress phase separation. The organic memory diodes exhibit well reproducible and prominent current bistability and good charge retention characteristics free from phase separation issues. Nondestructive spectroscopic ellipsometry is used to characterize the physical properties of the polymer/nanoparticle composites, such as the polymers effective dielectric function/layer thickness and the Au nanoparticles effective volume fraction, which are important parameters for gaining insightful information on charge transport in this system. Temperature-dependent analysis of the read/write current behaviors suggests that charge transport in such a polymer/Au nanoparticle composite is dominated by carrier hopping via shallow-level traps at the high field regime.

2.2-inch QQVGA AMOLED driven by low temperature top-gate a-IGZO TFT

We investigated amorphous In₂O₃-Ga₂O₃-ZnO (a-IGZO) oxide semiconductor material as the active layer of TFTs. The top gate a-IGZO TFTs by using a conventional photolithography technique have good performance without an additional post annealing process. A 2.2- inch QQVGA AMOLED display was demonstrated by using a-IGZO TFT fabricated on glass substrate. The maximum process temperature is 200°C.