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Scaling down semiconductor lasers in all three dimensions hold the key to the developments of compact, low-threshold, and ultrafast coherent light sources, as well as photonic integrated circuits. However, the minimum size of conventional semiconductor lasers utilizing dielectric cavity resonators (photonic cavities) is limited by the diffraction limit. Recently, it has been proposed and experimentally demonstrated that the use of plasmonic cavities based on metal-oxide-semiconductor (MOS) nanostructures can break this limit. In this talk, I will report on the recent progress of plasmonic nanolasers using MOS structures. In particular, by using alloy-composition-varied indium gallium nitride/gallium nitride (In x Ga 1−x Ga@GaN) core-shell nanorods as the nanolaser gain media in the full visible spectrum, we are able to demonstrate allcolor nanolasers that can be operated with ultralow continuous-wave lasing thresholds and single lasing modes. Very recently, we have also succeeded in developing nanorod-array plasmonic lasers based on a metal-all-around nanorod MOS structure, which can be fabricated on a wafer scale. The group-III-nitride nanorods in these 2D arrays behave as an ensemble of random dielectric media, whereby Anderson localization of light occurs in a spatially confined area. Due to the light localization, the lasing phenomenon above the optical pumping threshold shows a strong self-focusing behavior.

Diffraction-unlimited semiconductor nanolasers are demonstrated by using single shape-controlled InGaN/GaN core-shell nanorods as laser gain media on Ag films epitaxially grown on Si substrates. The use of atomically smooth Ag films allows us to fabricate low-loss plasmonic cavities for ultralow-threshold, continuous-wave (CW) nanolaser operation above liquid nitrogen temperature. Furthermore, the tunable band-gap energy of the InxGa1-xN alloy makes it possible to realize laser emission in the full visible spectrum.

A fast initial decay was observed from InN nanorods with ~30 nm diameter, the lifetime of which is much shorter than the carrier cooling time, demonstrating the substantial surface-associated influence on carrier relaxation in nanorods.

Abnormal temperature dependence of peak energy and bandwidth of photoluminescence spectra was observed for InN nanorods with a diameter

The diffraction limit imposes a fundamental technology barrier in optoelectronics, photonics, and information technology. In the past decade, a new discipline coined as “plasmonics” has emerged as an enabling technology not only to overcome the diffraction limit, but also to enhance the capabilities of light harvesting (solar cells), emission (light-emitting devices), and detection (optical detectors and sensors). In the paper, several new developments including fabrication of plasmonic structures or metamaterials (artificially structured materials exhibiting unusual and tunable plasmonic properties), optical nanoantennas, and nanolasers are described. The emergence of plasmonic devices can enable a fundamental paradigm shift in designing optical components and optoelectronic devices in the deep subwavelength regime.

The packaging and integration of calcium ion (Ca2+) ISFET sensor chips is a challenge to sensor technology and materials. This study used ultrathin InN ion sensitive sensor (∼10 nm) with gate region functionalized with phosphotyrosine (p-Tyr) to detect calcium ion (Ca2+) in aqueous solution. The miniaturized InN sensor provides to integrate with existing medical equipment for real-time and continuous monitoring of human blood, the sensor was miniaturized to 100 μm by 400 μm and integrated at the tip of hypodermic injection needle (18G). The sensor has current variation ratio of 1.11% with per decade change of Ca2+ and a detection limit of 10−6 M. The response time is 5 seconds.

These keynote speeches discuss the following:bottom-up assembled plasmonic metamaterials for applications in nanophotonics; emergence of on-chip robotics for biomedical innovations; sensor challenges for future bio and biomed applications; miniaturized biomedical system for diagnostic and therapeutic application; and radiosynthesis on EWOD platform for positron emission tomography (PET) imaging.

Vertically self-aligned gallium nitride nanorod arrays grown by plasma-assisted molecular-beam epitaxy are shown to behave as subwavelength optical media in both their discrete and integrated forms, which have important implications for optoelectronic applications.

Zinc oxide (ZnO) has been attractive for optoelectronics application due to its wide band gap (E g =3.37 eV) and large exciton binding energy (~60 meV) characteristics. However, p-type doping of ZnO is still controversial and problematic. Therefore, there is considerable interest in fabrication of n-ZnO/p-GaN heterojunction LEDs. In this work, we fabricated the LEDs consisting of n-ZnO nanorod arrays on p-GaN substrate. ZnO nanorod arrays were fabricated by a hydrothermal method. Hydrothermal methods have the advantage that they are simple, inexpensive and environmentally friendly. However, nanorods fabricated by hydrothermal methods typically have large numbers of defects due to the low growth temperature (90 °C). The defect related photoluminescence (PL) is significantly affected by annealing, and under suitable conditions it can be entirely eliminated. As- grown nanorods exhibit UV emission and large yellow defect emission which is likely due to the presence of OH groups. The PL spectra can be significantly improved by annealing the nanorods at 200 °C under Ar flow. Therefore we investigated the influence of argon annealing of ZnO nanorods on the performance of ZnO/GaN LEDs, as well as the influence of annealing environments. Devices with ZnO rod length ~ 250 nm were fabricated and the results obtained are discussed.

In this paper, we report the study of the optical properties of ZnO ribbon/comb nanostructures. The nanostructures were synthesized using a previously reported procedure, and they were characterized by scanning electron microscopy (SEM). The optical properties of ribbon/comb structures were studied using variable temperature photoluminescence with a HeCd laser excitation source (325 nm). Time-resolved photoluminescence (TRPL) was measured by using the Kerr gated fluorescence technique.

Non-volatile mass data storage using MEMS-based actuation and probe-based read/write has great potential to replace conventional semiconductor memories because of the achieved high areal density. From the standpoint of system implementation, the complexity for integration of all functional electronics in such a micro disk drive is enormously reduced by using CMOS-MEMS as the core implementing technology. In this paper, we present the latest progress in the MRM-based and the EFM-based storage devices that are currently under development.