Browsing by Author "Lee, Min-Hung"

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Coherent and Polarized Random Laser Emissions from Colloidal CdSe/ZnS Quantum Dots Plasmonically Coupled to Ellipsoidal Ag Nanoparticles
(2017-02)
Yao, Yung-Chi
;
Yang, Zu-Po
;
Hwang, Jung-Min
;
Su, Hai-Ching
;
Haung, Jing-Yu
This study demonstrates the capability of controlling optical anisotropy of lasing emissions by manipulating the coupling strength spatially and spectrally between the oscillated electric field of emitted light and the localized surface plasmon (LSP) resonance for a random lasing medium composed of colloidal CdSe/ZnS quantum dots (QDs) and ellipsoidal silver nanoparticles (Ag NPs). Distinctive from the amplified spontaneous emission generally observed on colloidal CdSe/ZnS QDs, it has been found that lasing emissions of the revealed system exhibit clear interference features (coherent optical feedbacks) with low-threshold characteristics, mainly attributed to enhanced light scatterings and optical gains arisen in peripheral surfaces of ellipsoidal Ag NPs. Importantly, the relative orientation, between the oscillated electric field of emitted light from colloidal CdSe/ZnS QDs and the ellipse axis of Ag NPs, plays a critical role in selective excitation of LSP resonances leading to laser emissions with preferential optical polarizations. The achievement of spatial and spectral coupling of LSP resonance with colloidal QDs, respectively, by spin coating thin QDs film on Ag NPs and control of the Ag NP geometry makes the present system one of the promising candidates of colloidal QDs-based random lasers to achieve coherent and polarized lasing emissions.
Correlation between ferroelectricity and nitrogen incorporation of undoped hafnium dioxide thin films
(2020-06-01)
Luo, Jun-Dao
;
Yeh, Yun-Tien
;
Lai, Yu-Ying
;
Wu, Chia-Feng
;
Chung, Hao-Tung
The ferroelectric characteristics of undoped hafnium oxide (HfO2) in titanium nitride (TiN)/HfO2/TiN stacks exhibited improved remanent polarization by controlling the nitrogen gas flow during TiN deposition in this work. Electrical measurements revealed that samples with a higher N-2/(Ar + N-2) ratio obtained a higher remanent polarization of approximately 10 mu C/cm(2) at 2.5 V but exhibited a larger leakage current and less reliability. Among all the samples, the sample with a N-2/(Ar + N-2) ratio of 33% exhibited a relatively high remanent polarization of 12 mu C/cm(2) and excellent endurance over 10(8) cycles. Through X-ray photoelectron spectroscopy (XPS) analysis, it was observed that increasing the N-2 gas flow during TiN electrode deposition contributed to excessive N-diffusion, leading to the creation of more oxygen vacancies and subsequently to device failure. Therefore, controlling the appropriate N-2 gas flow during TiN deposition is crucial to enhance the ferroelectric characteristics of undoped HfO2. The results of this study may be applicable to future work on nonvolatile memory applications.
Impact of Nanoscale Polarization Relaxation on Endurance Reliability of One-Transistor Hybrid Memory Using Combined Storage Mechanisms
(2015)
Chiu, Yu-Chien
;
Chang, Chun-Yen
;
Hsu, Hsiao-Hsuan
;
Cheng, Chun-Hu
;
Lee, Min-Hung
We demonstrate a novel hybrid nonvolatile memory integrated with a charge trapping mechanism and a ferroelectric polarization effect. The hybrid memory features a large threshold voltage window of 2V, fast 20-ns program/erase time, tight switching margin, and long 10(12)-cycling endurance at 85 degrees C. Such excellent endurance reliability at 85 degrees C can be ascribed to the introduction of charge-trapping node into the design of memory structure that not only weakens temperature-dependent polarization relaxation, but also improves high-temperature endurance reliability.
Improvement of ferroelectric properties in undoped hafnium oxide thin films using thermal atomic layer deposition
(2019-06-01)
Luo, Jun-Dao
;
Zhang, He-Xin
;
Wang, Zheng-Ying
;
Gu, Siang-Sheng
;
Yeh, Yun-Tien
Modulating the water pulse time during thermal atomic layer deposition is an effective approach to enhancing the ferroelectric properties of undoped HfO2 thin films. Through grazing incidence X-ray diffraction (GI-XRD), it was observed that a shorter water pulse time can inhibit formation of the monoclinic phase and thereby obtain good remanent polarization. Transmission electron microscopy (TEM) images and GIXRD analysis were used to reveal the crystallization conditions of the undoped HfO2 thin films. By modulating the water pulse time during deposition of all samples, no impurities were found in these films via X-ray photoelectron spectroscopy. Moreover, samples with shorter water pulse times revealed lower binding energy and higher leakage current. However, electric measurement results of samples with shorter water pulse times revealed a higher remanent polarization of approximately 9 mu C cm(-2) and a coercive field of similar to 1.95 MV cm(-1) compared with other samples. After endurance testing, the films lasted for more than 10(8) cycles at 2.25 V, so they are ideally suited to low-power ferroelectric CMOS devices and nonvolatile memory applications. (c) 2019 The Japan Society of Applied Physics
Interface Polarization Fluctuation Effect of Ferroelectric Hafnium-Zirconium-Oxide Ferroelectric Memory with Nearly Ideal Subthreshold Slope
(2015)
Chiu, Yu-Chien
;
Cheng, Chun-Hu
;
Fan, Chia-Chi
;
Chen, Po-Chun
;
Chang, Chun-Yen
Low Power 1T DRAM/NVM Versatile Memory Featuring Steep Sub-60-mV/decade Operation, Fast 20-ns Speed, and Robust 85 degrees C-Extrapolated 10(16) Endurance
(2015)
Chiu, Yu-Chien
;
Cheng, Chun-Hu
;
Chang, Chun-Yen
;
Lee, Min-Hung
;
Hsu, Hsiao-Hsuan
In this work, we report a one-transistor (1T) versatile memory; the memory transistor characteristics achieve sub-60-mV/dec operation and considerably low off-state leakage of 10(-15) A/mu m at a supply voltage below 0.5V. The versatile memory features DRAM/NVM functions of large Delta V-T window of 2.8V, fast 20-ns speed, 10(3)s retention at 85 degrees C, and long extrapolated 10(16) endurance at 85 degrees C, which show the potential for 3D memory application with severe requirement on both high density and low power consumption.
Monolithic integration of GaN-based light-emitting diodes and metal-oxide-semiconductor field-effect transistors
(2014-10-20)
Lee, Ya-Ju
;
Yang, Zu-Po
;
Chen, Pin-Guang
;
Hsieh, Yung-An
;
Yao, Yung-Chi
In this study, we report a novel monolithically integrated GaN-based light-emitting diode (LED) with metal-oxide-semiconductor field-effect transistor (MOSFET). Without additionally introducing complicated epitaxial structures for transistors, the MOSFET is directly fabricated on the exposed n-type GaN layer of the LED after dry etching, and serially connected to the LED through standard semiconductor-manufacturing technologies. Such monolithically integrated LED/MOSFET device is able to circumvent undesirable issues that might be faced by other kinds of integration schemes by growing a transistor on an LED or vice versa. For the performances of resulting device, our monolithically integrated LED/MOSFET device exhibits good characteristics in the modulation of gate voltage and good capability of driving injected current, which are essential for the important applications such as smart lighting, interconnection, and optical communication. (C) 2014 Optical Society of America
Monolithic integration of GaN-based light-emitting diodes and metal-oxide-semiconductor field-effect transistors: reply
(2018-01-22)
Lee, Ya-Ju
;
Yang, Zu-Po
;
Chen, Pin-Guang
;
Hsieh, Yung-An
;
Yao, Yung-Chi
We present some comments to the paper "Monolithic integration of GaN-based light-emitting diodes and metal-oxide-semiconductor field-effect transistors: comment" [Opt. Express 22, A1589 (2014)]. (C) 2017 Optical Society of America under the terms of the OSA Open Access Publishing Agreement
Negative-Capacitance FinFET Inverter, Ring Oscillator, SRAM Cell, and Ft
(2018-01-01)
Li, Kai-Shin
;
Wei, Yun-Jie
;
Chen, Yi-Ju
;
Chiu, Wen-Cheng
;
Chen, Hsiu-Chih
In this work, we use thermal-ALD to prepare ferroelectric HfZrO2 (HZO) thin film with thickness from 3 to 7 nm for the NC-FinFET's gate stack. The subthreshold swing (SS) was as low as 5 mV/dec (SSmin) over 4 orders of I-D. Lower thermal budget process, CO2 far-infrared laser activation and 400 degrees C Ni silicide are employed in the 2-level metal backend integration for maintaining the orthorhombic phase in HZO thin film and minimizing the hysteresis in IV. NC-FinFET inverter has 77% higher voltage gain compared to FinFET-inverter employing HfO2 gate dielectric. NC-FinFET ring oscillator exhibit small speed and power advantages over FinFET oscillator. For the first time, NC-FET cut-off frequency (F-t) frequency is measured, 23.1 GHz or 23% higher than the control FET Ft. NC-FinFET SRAM was observed to exhibit large noise margin.
On the Variability of Threshold Voltage Window in Gate-Injection Versatile Memories with Sub-60mV/dec Subthreshold Swing and 10(12)-Cycling Endurance
(2016)
Chiu, Yu-Chien
;
Chang, Chun-Yen
;
Yen, Shiang-Shiou
;
Fan, Chia-Chi
;
Hsu, Hsiao-Hsuan
Incorporating a charge-trapped ZrSiO with ferroelectric HfZrO dielectrics, we demonstrated a gate-injection versatile memory with sub-60mV/dec subthreshold swing (SS) and large threshold voltage window (Delta V-T) of >2V under a fast 20-ns speed. Moreover, it is revealed that the local defects at ZrSiO/HfZrO interface affect the ferroelectric negative capacitance tuning and thus increases the variability of V-T and SS during 10(12) cycling endurance.
Plasmonically Induced Coherent and Polarized Random Laser Emissions in Colloidal CdSe/ZnS Quantum Dots with Ellipsoidal Ag Nanoparticles
(2017-01-01)
Yao, Yung-Chi
;
Yang, Zu-Po
;
Haung, Jing-Yu
;
Lee, Min-Hung
;
Lee, Ya-Ju
We demonstrate the capability of controlling the optical anisotropy of lasing emissions by manipulating the coupling between the oscillated electric field and the localized surface plasmon (LSP) resonance for a random lasing medium composed of colloidal CdSe/ZnS quantum dots (QDs) and ellipsoidal silver nanoparticles (Ag NPs). Distinctive from the amplified spontaneous emission (ASE) generally observed on the CdSe/ZnS QDs, it has been found that lasing emissions of the revealed system exhibit clear interference features with low-threshold characteristics, mainly attributed to enhanced light scatterings and optical gains arisen in the peripheral surfaces of ellipsoidal Ag NPs. Importantly, the relative orientation, between the oscillated electric field of emitted light from CdSe/ZnS QDs and the ellipse axis of Ag NPs, plays a critical role in selective excitation of LSP resonances leading to the laser emissions with preferential optical polarizations. That is further examined and validated by the finite-difference time-domain simulation. The achievement of spatial and spectral coupling of LSP resonance with colloidal QDs respectively make the present system one of the promising candidates of colloidal QDs-based random lasers to achieve coherent and polarized lasing emissions.
Reliable Doping Technique for WSe2 by W: Ta Co-Sputtering Process
(2016)
Chien, Po-Yen
;
Zhang, Ming
;
Huang, Shao-Chia
;
Lee, Min-Hung
;
Hsu, Hung-Ru
The electrical and material properties of WSe2 doped by W:Ta co-sputtering process were examined. High acceptor doping concentration (6x10(13)cm(-2)) and good effective hole mobility (16.5cm(2)/Vs) were realized. As a result, low sheet resistance (17k Omega/sq) and contact resistance with Pd metal (11.4k Omega-mu m) were measured using TLM structures.
Simulation-based study of negative-capacitance double-gate tunnel field-effect transistor with ferroelectric gate stack
(2016-04-01)
Liu, Chien
;
Chen, Ping-Guang
;
Xie, Meng-Jie
;
Liu, Shao-Nong
;
Lee, Jun-Wei
The concept of ferroelectric (FE) negative capacitance (NC) may be a turning point in overcoming the physical limitations imposed by the Boltzmann tyranny to realize next-generation state-of-the-art devices. Both the body factor (m-factor) and the transport mechanism (n-factor) are simultaneously improved by integrating an NC with a tunnel FET (TFET). The modeling approach is discussed in this study as well as the NC physics. By optimizing the thicknesses of FE, semiconductor, and interfacial layers, the capacitance of the FE layers is modulated to match that of a MOS resulting in the smallest subthreshold swing that is also hysteresis-free. An ultrathin-body double gate tunnel FET (UTB-DG-TFET) exhibits a steep slope (a subthreshold swing below 10 mV/dec over more than 4 orders of magnitude) for low-power applications (<0.2V switching voltage) to realize next-generation state-of-the-art devices. (C) 2016 The Japan Society of Applied Physics
Simulation-based study of negative-capacitance double-gate tunnel field-effect transistor with ferroelectric gate stack
(2016-04)
Liu, Chien
;
Chen, Ping-Guang
;
Xie, Meng-Jie
;
Liu, Shao-Nong
;
Lee, Jun-Wei
The concept of ferroelectric (FE) negative capacitance (NC) may be a turning point in overcoming the physical limitations imposed by the Boltzmann tyranny to realize next-generation state-of-the-art devices. Both the body factor (m-factor) and the transport mechanism (n-factor) are simultaneously improved by integrating an NC with a tunnel FET (TFET). The modeling approach is discussed in this study as well as the NC physics. By optimizing the thicknesses of FE, semiconductor, and interfacial layers, the capacitance of the FE layers is modulated to match that of a MOS resulting in the smallest subthreshold swing that is also hysteresis-free. An ultrathin-body double gate tunnel FET (UTB-DG-TFET) exhibits a steep slope (a subthreshold swing below 10 mV/dec over more than 4 orders of magnitude) for low-power applications (<0.2V switching voltage) to realize next-generation state-of-the-art devices. (C) 2016 The Japan Society of Applied Physics