Recruits

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Postdoctoral Position in Perovskite Solar…

2020-12-04 Hits:815

Postdoctoral Position in Perovskite Solar Cells (Locati...

Ph.D. position in Perovskite Solar…

2020-12-04 Hits:580

Ph.D. position in Perovskite Solar Cells (Location: Tai...

Invitation of Applications for Multiple…

2020-10-14 Hits:858

Candidates are expected to have a Ph.D. degree in scien...

Speeches

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12/28 Seminar Speech

Hits:623

SpeakerMr. Tsai Song Jau 

OrganizationChina Steel Corporation

12/21 Seminar Speech

Hits:556

SpeakerProfessor Yi-Chia Chou

OrganizationDepartment of Electrophysics, National Chiao Tung University  

12/14 Seminar Speech

Hits:508

SpeakerMr. Yiren Wu

OrganizationPhrozen 

12/07 Seminar Speech

Hits:487

SpeakerProfessor Chen-Tsyr Lo

OrganizationDepartment of Materials and Optoelectronic Science, National Sun Yat-Sen University  

TopicSynthesis and Applications of Functional Cross-linked Core-shell Block Copolymers

 Date10:20 am 2020.12.07

LocationRoom 203, College of Engineering

Abstract;A series of high-performance cross-linked core-shell block copolymers as charge-storage or ion-conductive materials will be introduced. We have been studied in the functional core-shell block-copolymer nanoparticles with cross-linking conjugating cores surrounding by hydrophilic shells via Suzuki-coupling reaction, while the nanoparticles with cross-linked cores using triazole-based comprising several ion-conductive functional groups, such as the zwitterionic groups or triazolium groups with salts or ion liquids were also studied. The nanoparticles presented uniform size distribution and well-defined core-shell nanostructure, while the intra-molecular charge transfer was effectively enhanced due to the incorporation of conjugating groups. Both the conjugating-core sizes and π-π interaction of the prepared nanoparticles were effectively controlled by the block composition. Moreover, the studied transistor memory devices embedded with these solution-process-able nanoparticles exhibited non-volatile flash-type memory characteristics and presented both amphiphilic carrier-trapping abilities. For those ionic-conductive nanoparticles, the highest ionic conductivities of 1.26 × 10–3 S/cm were achieved at 90 oC with the presence of 30 wt.% ionic liquid, which are due to the enhanced segmental molecular motion and the formation of a preferable ionic-conductive path composed of the hydrophobic ionic-liquid based shell with the added ionic liquid. We believe this achievement provides multiple applications of cross-linked nanoparticles as a promising candidate for both charge-storage and ion-conductive materials in the future organic technology.

11/30 Seminar Speech

Hits:520

SpeakerProfessor PI-HO HU

OrganizationDepartment of Electrical Engineering, National Taiwan University  

TopicFerroelectric FET Non-volatile Memory

 Date10:20 am 2020.11.30

LocationRoom 203, College of Engineering

Abstract;Artificial intelligence (AI) and Internet-of-Things (IoT) play a vital role in the future. For the von Neumann architecture, communication bottleneck between memory and processors becomes one of the most series problems due to low data throughput and high-power consumption. Non-volatile memory (NVM) based synapse and logic-in-memory circuit have been proposed to alleviate these problems. Ferroelectric Field-Effect-Transistor (FeFET) has been explored actively for emerging non-volatile memory and neuromorphic computing due to its high compatibility with CMOS platform. In this talk, I will introduce the operation principles and the challenges of FeFET memory. We have proposed a novel split-gate FeFET (SG-FeFET) for non-volatile memory and neuromorphic applications, which significantly improves the energy efficiency and reduces the power consumption. The reliability and endurance of SG-FeFET memory have also been improved owing to the lowered write voltage. SG-FeFET as a synaptic device has also been investigated including the non-linearity, asymmetry, and dynamic range of conductance updates.

11/23 Seminar Speech

Hits:570

SpeakerProfessor Chia-Shain Chuang

OrganizationDepartment of Electronic Engineering, Chung Yuan Christian University  

TopicInvestigations for magnetoresistance of ultralow-hole-density monolayer epitaxial graphene grown on SiC systems

 Date10:20 am 2020.11.23

LocationRoom 203, College of Engineering

Abstract;In this talk, I focus on detailed measurements on ultralow-density p-type monolayer epitaxial graphene, which has yet to be extensively studied. The measured resistivity ρxx shows insulating behavior in the sense that ρxx decreases with increasing temperature T over a wide range of T (1.5 K ≤ T ≤ 300 K). The crossover from negative magnetoresistivity (MR) to positive magnetoresistivity at T = 40 K in the low-field regime is ascribed to a transition from low-T quantum transport to high-T classical transport. For T ≥ 120 K, the measured positive MR ratio [ρxx(B) − ρxx(B = 0)]/ρxx(B = 0) at B = 2 T decreases with increasing T, but the positive MR persists up to room temperature. Our experimental results suggest that the large MR ratio (~100% at B = 9 T) is an intrinsic property of ultralow-charge-density graphene, regardless of the carrier type. This effect may find applications in magnetic sensors and magnetoresistance devices.
Keywords: epitaxial graphene, resistance standard, magnetoresistance, quantum hall

11/16 Seminar Speech

Hits:563

SpeakerProfessor Pin-Jui Hsu

OrganizationDepartment of Physics, National Tsing Hua University  

TopicProximity-Effect-Induced Superconductivity in Monatomic Ni-Pb Alloy and Ni Nanoislands

 Date10:20 am 2020.11.16

LocationRoom 203, College of Engineering

Abstract;Proximity effect facilitates the penetration of Cooper pairs that permits superconductivity in normal metal with reduced dimensionality, offering a promising approach to develop novel quantum phenomena and emergent phases of matters in hybrid magnetic/superconducting nanostructures. Here, we have investigated proximity-induced superconductivity in monatomic Ni-Pb alloy and Ni nanoislands grown on Pb(111) by scanning tunneling microscopy/ spectroscopy (STM/STS) combined with theoretical calculations. Through elemental Pb superconducting substrate, tunneling conductance spectra have resolved an induced superconductivity with a gap size Δ about 0.85 meV in Ni-Pb alloy, which is about 0.11 meV smaller than Pb(111). On the contrary, Ni nanoislands with honeycomb lattice display a superconductivity gap with the same size of the Pb(111) substrate. From spatially monotonic decrease of Δ across the interface between Ni-Pb alloy and Pb(111), the decay length ξL about 5 nm has been extracted. According to the Usadel fittings and the BdG model, a weak ferromagnetism with an effective temperature about 6 ~ 15 K explains such rather short decay length as well as reduced superconductivity gap in the Ni-Pb surface alloy. As for honeycomb-structured Ni nanoislands, asymmetric edge scattering of surface electrons on Pb(111) has been revealed and further theoretical insights on the details of strong suppression of backscattering at the bearded type of edges are currently in progress.

11/02 Seminar Speech

Hits:549

Speaker:Dr. Tien-Ming Chuang

Topic: Visualizing Emergent Superconductivity by Spectroscopic Imaging - Scanning Tunneling Microscopy

10/26 Seminar Speech

Hits:771

Speaker: Professor Hsin-Jay Wu

Topic: Phase diagram engineering - A New Avenue Towards High Performance Thermoelectric Materials