Browsing by Author "Lin, Sheng-Di"

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A delta-doped quantum well system with additional modulation doping
(2011)
Luo, Dong-Sheng
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Lin, Li-Hung
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Su, Yi-Chun
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Wang, Yi-Ting
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Peng, Zai Fong
A delta-doped quantum well with additional modulation doping may have potential applications. Utilizing such a hybrid system, it is possible to experimentally realize an extremely high two-dimensional electron gas (2DEG) density without suffering inter-electronic-subband scattering. In this article, the authors report on transport measurements on a delta-doped quantum well system with extra modulation doping. We have observed a 0-10 direct insulator-quantum Hall (I-QH) transition where the numbers 0 and 10 correspond to the insulator and Landau level filling factor nu = 10 QH state, respectively. In situ titled-magnetic field measurements reveal that the observed direct I-QH transition depends on the magnetic component perpendicular to the quantum well, and the electron system within this structure is 2D in nature. Furthermore, transport measurements on the 2DEG of this study show that carrier density, resistance and mobility are approximately temperature (T)-independent over a wide range of T. Such results could be an advantage for applications in T-insensitive devices.
A Spin-controlled Microcavity Laser
(2015)
Hsu, Feng-Kuo
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Xie, Wei
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Lee, Yi-Shan
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Lin, Sheng-Di
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Lai, Chih-Wei
We demonstrate highly circularly polarized lasing under non-resonant elliptically polarized optical pumping in a semiconductor microcavity at room temperature. (C) 2014 Optical Society of America
An Anomalous Conductance Decrease in Charge Sensitive Infrared Phototransistor
(2013-01-01)
Kang, Ting-Ting
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Komiyama, Susumu
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Ueda, Takeji
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Lin, Shi-Wei
;
Lin, Sheng-Di
For charge-sensitive infrared phototransistors (CSIP), it is observed that "conductance decrease," which is contrary to the standard "conductance increase" photon response, can also happen after absorbing infrared light. By experimental modeling the charge-up detection mechanism of CSIP via a capacitive way, we clarify that " conductance decrease" should be attributed to the significantly reduced low quantum well electron mobility after the photon-charging process, rather than a reversed electron transfer. This experimental result clearly indicates that photon-induced charges are able to modify the electron mobility in those "charge-sensitive sensor" types of semiconductor quantum single-photon detectors.
Anomalous optical magnetic shift of self-assembled GaSb/GaAs quantum dots
(2011-07-01)
Lin, Ta-Chun
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Li, Liang-Chen
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Lin, Sheng-Di
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Suen, Yuen-Wuu
;
Lee, Chien-Ping
We report the magneto-photoluminescence (PL) measurement results on type-II self-assembled GaSb/GaAs quantum dots with the magnetic field applied in Faraday and Voigt configurations. The emission of the quantum dots exhibited a typical diamagnetic blueshift when the magnetic field was applied in a Faraday configuration. However, when the magnetic field was in the Voigt configuration, an unusual redshift in the emission peak accompanied with a rapid increase of the PL intensity was observed. Guided by numerical calculations, the magnetic field applied in the Voigt configuration is found to provide an additional vertical confinement to electrons, and therefore, substantially enhance the radiative electron-hole recombination. The resulting decrease of the steady-state hole concentration gives rise to the observed anomalous magnetic redshift. (C) 2011 American Institute of Physics. [doi:10.1063/1.3607973]
Anticorrelation between the splitting and polarization of the exciton fine structure in single self-assembled InAs/GaAs quantum dots
(2011-02-28)
Lin, Chia-Hsien
;
You, Wen-Ting
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Chou, Hsiang-Yu
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Cheng, Shun-Jen
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Lin, Sheng-Di
We report on a systematic correlation between the fine-structure splitting and polarization anisotropy of excitons in InAs/GaAs quantum dots, but with an unexpected reversal in order of the polarization eigenaxes. Such an anticorrelation is explained by a large valence-band-mixing induced splitting due to the shape and strain anisotropies. The strength and phase of valence band mixing are also found to play an important role in the tuning of fine structure splitting using an in-plane magnetic field.
Antimonidation of ultrathin epitaxial aluminum nanofilms for metamorphic growth of Sb-based structures on GaAs substrates
(2020-04-01)
Wu, Yu-Hsun
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Wu, Jenq-Shinn
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Lin, Sheng-Di
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電子工程學系及電子研究所
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Department of Electronics Engineering and Institute of Electronics
The narrow-bandgap Sb-based semiconductors find their potential in various kinds of device applications such as high-speed, low-power transistors and mid-infrared diode lasers. However, epitaxial growth on the substrates that are commercially available in large sizes (for example, GaAs and Si) faces the fundamental challenge of lattice mismatch. Different from the conventional metamorphic growth employing a thick buffer, we adopt the approach of transforming an ultrathin epitaxial aluminum (Al) nanofilm into epitaxial AlSb to serve as the template for growth of antimonide structures. It is found that the process named "antimonidation" plays a critical role in Sb-based metamorphic growth. Our experimental results provide practical usefulness for growing semiconductor devices on lattice-mismatched substrates without using thick metamorphic buffer layers. (C) 2020 The Japan Society of Applied Physics
Atomic-scale epitaxial aluminum film on GaAs substrate
(2017-07-01)
Fan, Yen-Ting
;
Lo, Ming-Cheng
;
Wu, Chu-Chun
;
Chen, Peng-Yu
;
Wu, Jenq-Shinn
Atomic-scale metal films exhibit intriguing size-dependent film stability, electrical conductivity, superconductivity, and chemical reactivity. With advancing methods for preparing ultra-thin and atomically smooth metal films, clear evidences of the quantum size effect have been experimentally collected in the past two decades. However, with the problems of small-area fabrication, film oxidation in air, and highly-sensitive interfaces between the metal, substrate, and capping layer, the uses of the quantized metallic films for further ex-situ investigations and applications have been seriously limited. To this end, we develop a large-area fabrication method for continuous atomic-scale aluminum film. The self-limited oxidation of aluminum protects and quantizes the metallic film and enables ex-situ characterizations and device processing in air. Structure analysis and electrical measurements on the prepared films imply the quantum size effect in the atomic-scale aluminum film. Our work opens the way for further physics studies and device applications using the quantized electronic states in metals. (C) 2017 Author(s).
Berezinskii-Kosterlitz-Thouless transition in an Al superconducting nanofilm grown on GaAs by molecular beam epitaxy
(2020-05-15)
Su, Guan-Ming
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Wu, Bi-Yi
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Fan, Yen-Ting
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Kumar, Ankit
;
Chang, Chau-Shing
We have performed extensive transport experiments on a 4 nm thick aluminum (Al) superconducting film grown on a GaAs substrate by molecular beam epitaxy (MBE). Nonlinear current-voltage (I-V) measurements on such a MBE-grown superconducting nanofilm show that V similar to I-3, which is evidence for the Berezinskii-Kosterlitz-Thouless (BKT) transition, both in the low-voltage (T-BKT 1.97 K) and high-voltage regions (T-BKT 2.17 K). In order to further study the two regions where the I-V curves are BKT-like, our experimental data are fitted to the temperature-induced vortices/antivortices unbinding model as well as the dynamical scaling theory. It is found that the transition temperature obtained in the high-voltage region is the correct T-BKT as confirmed by fitting the data to the aforementioned models. Our experimental results unequivocally show that I-V measurements alone may not allow one to determine T-BKT for superconducting transition. Therefore, one should try to fit one's results to the temperature-induced vortices/antivortices unbinding model and the dynamical scaling theory to accurately determine T-BKT in a two-dimensional superconductor.
Characteristic of UV Plasmonic Nanolasers with Different Spacer Thickness
(2016)
Chou, Yu-Hsun
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Chou, Bo-Tsun
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Lin, Sheng-Di
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Lin, Tzy-Rong
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Lin, Chien-Chung
We report on plasmonic lasers with ZnO nanowire lying on single-crystalline silver film with different SiO2 thickness spacer. Spacer thickness were optimized to adjust the surface plasmon dispersion curve and resulting different group index.
Characterization of Single-Crystalline Aluminum Thin Film on (100) GaAs Substrate
(2013-04-01)
Lin, Shi-Wei
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Wu, Jau-Yang
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Lin, Sheng-Di
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Lo, Ming-Cheng
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Lin, Ming-Huei
We have studied the structure and physical properties of an aluminum thin film grown on a (100) GaAs substrate. The X-ray diffraction (XRD) data shows that the Al film grown in situ by molecular beam epitaxy (MBE) is single crystalline. Compared with the polycrystalline film ex situ evaporated using an electron-gun (E-gun), the MBE-grown Al film has a high optical reflectivity in the visible and ultraviolet (UV) regime. In addition, the MBE-grown film has a 2-order-lower residue resistance, a 1-order-higher temperature coefficient of resistance, and a 2-order-larger magnetoresistance (MR) than the polycrystalline film. Owing to the long mean free time, the bulk-like electron-to-hole transition of Hall resistivity is observed for the first time in a nanoscale metal thin film. Our results suggest that MBE-grown Al thin films have great potential applications in metal-based nanoelectronics and nanophotonics. (C) 2013 The Japan Society of Applied Physics
CMOS Single-Photon Detectors for Vehicle LiDAR - Status and Trends
(2018-01-01)
Lin, Sheng-Di
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交大名義發表
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National Chiao Tung University
Constant Excess Bias Control for Single-Photon Avalanche Diode Using Real-Time Breakdown Monitoring
(2015-08-01)
Chang, Po-Hsuan
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Tsai, Chia-Ming
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Wu, Jau-Yang
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Lin, Sheng-Di
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Kuo, Ming-Ching
A monolithic constant excess bias control circuit for single-photon avalanche diode (SPAD) in standard 0.18-mu m CMOS technology is reported. The proposed real-time breakdown monitoring technique is incorporated into a passive-quenching-active-reset circuit. A sample-and-hold circuit samples the breakdown level of SPAD through well-defined sampling phase. Following the sample-and-hold circuit, the level shifter with voltage shifting defined by predetermined excess bias provides the reset voltage of SPAD. The design operates the SPAD under constant excess bias and effectively mitigates the impact of the process-voltage-temperature variation by maintaining the optimal excess bias condition.
Controllable Disorder in a Hybrid Nanoelectronic System: Realization of a Superconducting Diode
(2013-07-24)
Lo, Shun-Tsung
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Chen, Kuang Yao
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Lin, Sheng-Di
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Wu, J-Y.
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Lin, T. L.
We have studied a hybrid nanoelectronic system which consists of an AlGaAs/GaAs two-dimensional electron gas (2DEG) in close proximity (similar to 70 nm) to an Al superconducting nanofilm. By tuning the current through the Al film, we can change the conductance of the 2DEG and furthermore vary the effective disorder in the Al superconducting film in a controllable way. When a high current is injected into the film, screening which couples the Al film and the 2DEG results in a collapse of anti-symmetric behavior in the current-voltage characteristics, V(I) similar to - V(-I), which holds true in a conventional superconductor. Our results may open a new avenue of experimentally realizing a superconducting diode.
Crossover from negative to positive magnetoresistance in a Si delta-doped GaAs single quantum well
(2010-07-01)
Lo, Shun-Tsung
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Chen, Kuang Yao
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Su, Yi-Chun
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Liang, C. -T.
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Chang, Y. H.
We have performed magnetoresistance measurements on a Si delta-doped GaAs single quantum well With increasing temperature T, a crossover from negative magnetoresistance (NMR) to positive magnetoresistance (PMR) can be observed Our experimental results suggest that such a crossover corresponds to a transition from variable range hopping regime to activated electron transport. This is also consistent with the measured non-monotonic carrier density dependence on T. (C) 2010 Elsevier Ltd All rights reserved.
Crosstalk Between Single-Photon Avalanche Diodes in a 0.18-mu m High-Voltage CMOS Process
(2018-02-01)
Wu, Dai-Rong
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Tsai, Chia-Ming
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Huang, Yi-Hsiang
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Lin, Sheng-Di
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電子工程學系及電子研究所
Crosstalk between single-photon avalanche diodes (SPADs) fabricated by the standard CMOS process is extensively investigated. The dependence of device structure, device-to-device distance, and bias voltage on crosstalk has been experimentally studied. Our work reveals that direct-path optical crosstalk dominates in these CMOS SPADs, which is also confirmed with the first time-correlated crosstalk measurement. This work is valuable for SPAD array design and optimization in CMOS technology.
Design and demonstration of high quality-factor H1-cavity in two-dimensional photonic crystal
(2013-11-15)
Fu, Ying-Jhe
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Lee, Yi-Shan
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Lin, Sheng-Di
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電子工程學系及電子研究所
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Department of Electronics Engineering and Institute of Electronics
We introduce a method for designing an H1 photonic crystal cavity to enhance its quality factor (Q factor). The highest theoretical Q factor of 120,000 is obtained. The Fourier transformation of field distribution shows that the enhancement arises from the component reduction of a leaky mode. The Q-factor improvement has also been demonstrated experimentally with the highest value of 11,700. Our design could be useful for studying light-matter interaction in an H1 cavity as the mode volume only increases slightly. (C) 2013 Optical Society of America
DESIGN OF A NEAR-INFRARED SURFACE-EMITTING METALLIC NANOCAVITY WITH MULTIPLE QUANTUM WELL
(2014-01-01)
Chou, Bo-Tsun
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Lin, Sheng-Di
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交大名義發表
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National Chiao Tung University
We design an electrically-injected surface-emitting laser with metallic nanocavity aiming for near infrared regime. Our calculation shows that threshold gain and effective mode volume of the TE01 mode could achieve 2711 cm(-1) and 0.014 lambda(3)(0), respectively.
Design of Bottom-Emitting Metallic Nanolasers Integrated With Silicon-On-Insulator Waveguides
(2015-05-15)
Chou, Bo-Tsun
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Lu, Tien-Chang
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Lin, Sheng-Di
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交大名義發表
;
National Chiao Tung University
We propose and analyze a bottom-emitting metallic nanolaser with a cavity size smaller than one wavelength in three dimensions. We optimize the nanolaser performance by adjusting the thickness of SiNx insulator layer, pillar radius, p-cladding, and n-cladding layers. With a proper design, we can achieve the TE01 mode lasing with an extremely small effective mode volume of 0.135 (lambda(0) /n)(3) and an ultra low threshold gain of 247 cm(-1). The nanolaser is integrated with a silicon-on-insulator waveguide through a bottom-connected grating coupler. By properly modifying the grating coupler period, fill factor, shift position, and grating height, a high coupling efficiency of 88.5% can be acquired.
Diamagnetic Response of Exciton Complexes in Semiconductor Quantum Dots
(2008-12-31)
Tsai, Ming-Fu
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Lin, Hsuan
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Lin, Chia-Hsien
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Lin, Sheng-Di
;
Wang, Sheng-Yun
We report measurements of diamagnetic shifts for different exciton complexes confined in small InAs quantum dots. The measured diamagnetic responses are sensitive to the number of carriers in the exciton complexes, with systematic differences between neutral excitons, biexcitons, and trions. Theoretical calculations suggest that such systematic differences arise from very different extents of electron and hole wave functions confined in small quantum dots. The measured magnetic response of Coulomb energies is found to vary with the cube of the wave function extent, and can be a sensitive probe to the electron-hole wave function asymmetry.
Discrete monolayer light emission from GaSb wetting layer in GaAs
(2007-06-11)
Lo, Ming-Cheng
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Huang, Shyh-Jer
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Lee, Chien-Ping
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Lin, Sheng-Di
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Yen, Shun-Tung
Distinct light emission peaks from monolayers of GaSb quantum wells in GaAs were observed. Discrete atomic layers of GaSb for the wetting layer prior to quantum dot formation give rise to transition peaks corresponding to quantum wells with 1, 2, and 3 ML. From the transition energies the authors were able to deduce the band offset parameter between GaSb and GaAs. By fitting the experimental data with the theoretical calculated result using an 8x8 k center dot p Burt's Hamiltonian along with the Bir-Picus deformation potentials, the strain-free (fully strained) valence band discontinuity for this type-II heterojunction was determined to be 0.45 eV (0.66 eV). (c) 2007 American Institute of Physics.