Electro-optic properties of liquid crystal cells with nanowall electrodes.

This work fabricates a nanowall electrode for achieving advanced liquid crystal (LC) devices and improving LC displays. The nanowall electrode consists of indium-tin-oxide (ITO) sheets stacked with nanowalls, and the nanowalls have a height and thickness of 4 µm and 500 nm, respectively. The high aspect ratio (8.0) of the nanowalls sets the nanowall electrode apart from previous electrodes. A flat electrode that comprises only ITO sheets is used to evaluate the nanowall electrode. The LC cell with the nanowall electrode exhibits better electro-optic properties than the LC cell with the flat electrode due to the strong transverse electric field and small subelectrode gap of the nanowall electrode. Especially, the operating voltage (3.7 V) of the nanowall cell is 36% smaller than that (5.8 V) of the flat cell. Therefore, nanowall electrodes have potential in LC lenses, LC antennas, metaverse displays, and digital optics.

Formation of monodomain polymer-stabilized blue phase liquid crystals using surface acoustic waves.

This work uses surface acoustic waves (SAWs) that are generated by a piezoelectric substrate containing an interdigital transducer (IDT) to which a low voltage of 2 mV was applied at a frequency of 1 kHz to fabricate a polymer-stabilized blue phase liquid crystal (PS-BPLC) layer. The PS-BPLC layer has a more uniform optical microscope (OM) image at a voltage of 2 mV than at zero voltage, and its reflective spectrum exhibits a smaller full width at half maximum (FWHM) at the former than at the latter. The uniform OM image and small FWHM reveal that the lattices in the PS-BPLC layer have monodomain structure. The monodomain PS-BPLC layer is formed because the SAWs cause longitudinal and transverse vibrations of the PS-BPLC lattices in the vertical plane along their traveling direction. The proposed method for fabricating the monodomain PS-BPLC layer using the SAWs has potential for the development of reflective optical devices that consume low power during their fabrication.

Electrically controllable terahertz metamaterials with large tunabilities and low operating electric fields using electrowetting-on-dielectric cells.

A simple method that is compatible with all geometrical structures of terahertz (THz) metamaterials for increasing their frequency tunabilities and decreasing their operating electric fields is proposed. This method uses the displacement of glycerol droplets with various volumes to tune the resonance frequency of a THz metamaterial in an electrowetting-on-dielectric (EWOD) cell. The experimental results reveal that the THz metamaterial has a large frequency tunability of 28% at an operating electric field that is smaller than 0.2 V/µm as the glycerol droplets move in and out of the path of a THz beam. The frequency tunability is large because the near field of the metamaterial "experiences" a large difference between the refractive indices of glycerol and air. The EWOD cell with the THz metamaterial is a great achievement for developing electrically controllable band-stop filters with large frequency tunabilities and small operating electric fields.

Polymer LEDs with improved efficacy via periodic nanostructure-based aluminum.

Periodic aluminum-capped nanoslit arrays were produced on a polycarbonate plastic substrate by rapid hot embossing nanoimprint lithography and thermal evaporation, and they were used as a transparent window for blue-emitting polymer light-emitting diodes (PLEDs). The external quantum efficiency of blue-emitting PLEDs was enhanced by the surface plasmon polaritons of the periodic aluminum-capped nanoslit arrays. A maximum current efficiency of 4.84 cd/A was achieved for the proposed PLED, which was over 2.2 times that of the reference PLED (2.18 cd/A). These results demonstrate that periodic nanostructure can assist in the simple and low-cost fabrication of high-performance polymer optoelectronic devices.

A RRAM Integrated 4T SRAM with Self-Inhibit Resistive Switching Load by Pure CMOS Logic Process.

This paper reports a novel full logic compatible 4T2R non-volatile static random access memory (nv-SRAM) featuring its self-inhibit data storing mechanism for in low-power/high-speed SRAM application. With compact cell area and full logic compatibility, this new nv-SRAM incorporates two STI-ReRAMs embedded inside the 4T SRAM. Data can be read/write through a cross-couple volatile structure for maintaining fast accessing speed. Data can be non-volatilely stored in new SRAM cell through a unique self-inhibit operation onto the resistive random access memory (RRAM) load, achieving zero static power during data hold.