Browsing by Author "Lee, P. T."

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Design and fabrication of a InGaN vertical-cavity surface-emitting laser with a composition-graded electron-blocking layer
(2014-08-01)
Lin, B. C.
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Chang, Y. A.
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Chen, K. J.
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Chiu, C. H.
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Li, Z. Y.
In this study, the design and fabrication of a InGaN vertical-cavity surface-emitting laser (VCSEL) with a composition-graded electron blocking layer (GEBL) are revealed experimentally and theoretically. It has been demonstrated that laser output performance is improved by using a GEBL when compared to the typical VCSEL structure of a rectangular EBL. The output power obtained at 20 kA cm(-2) is enhanced by a factor of 3.8 by the successful reduction of threshold current density from 12.6 to 9.2 kA cm(-2) and the enlarged slope efficiency. Numerical simulation results also suggest that the improved laser output performances are due mainly to the reduction of electron leakage current and the enhanced hole injection efficiency in the multiple-quantum-well (MQW) active region.
Effect of the Thermal Characteristics of Phosphor for the Conformal and Remote Structures in White Light-Emitting Diodes
(2013-10-01)
Chen, K. J.
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Lin, B. C.
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Chen, H. C.
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Shih, M. H.
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Wang, C. H.
The influence of the thermal effect of phosphor for conformal and remote structures in white light-emitting diodes was investigated using the junction and phosphor temperatures. Comparing the measured temperatures with IR thermometer, the remote structure has a higher phosphor temperature than the conformal structure. This result indicates that the phosphor in the conformal structure has demonstrated superior conduction because of the high thermal conductivity in surrounding. Furthermore, thermal distribution in the simulation results has shown to have favorable agreement with the experimental results. Consequently, the lifetime measurement is shown to verify the results of the simulation and experiment for both structural types.
Flat band voltage control on low V(t) metal-gate/high-kappa CMOSFETs with small EOT
(2009-07-01)
Chin, Albert
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Chang, M. F.
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Lin, S. H.
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Chen, W. B.
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Lee, P. T.
The unwanted high threshold voltage (V(t)) is the major challenge for metal-gate/high-kappa CMOs especially at small equivalent-oxide-thickness (EOT). We have investigated the high V(t) issue that is due to flat-band voltage (V(fb)) roll-off at smaller EOT. A mechanism of charged oxygen vacancies formed by interface reaction was proposed to explain the V(fb) roll-off effect. This interface reaction can be decreased by inserting a thin interfacial SiON and using novel low temperature process. The self-aligned and gate-first metal-gate/high-kappa CMCSFETs using these methods have achieved low V(t) and good control of V(fb) roll-off at small 0.6-1.2 nm EOT. Crown Copyright (C) 2009 Published by Elsevier B.V. All rights reserved,
Flat band voltage control on low V-t metal-gate/high-kappa CMOSFETs with small EOT
(2009-07-01)
Chin, Albert
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Chang, M. F.
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Lin, S. H.
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Chen, W. B.
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Lee, P. T.
The unwanted high threshold voltage (V-t) is the major challenge for metal-gate/high-kappa CMOs especially at small equivalent-oxide-thickness (EOT). We have investigated the high V-t issue that is due to flat-band voltage (V-fb) roll-off at smaller EOT. A mechanism of charged oxygen vacancies formed by interface reaction was proposed to explain the V-fb roll-off effect. This interface reaction can be decreased by inserting a thin interfacial SiON and using novel low temperature process. The self-aligned and gate-first metal-gate/high-kappa CMCSFETs using these methods have achieved low V-t and good control of V-fb roll-off at small 0.6-1.2 nm EOT. Crown Copyright (C) 2009 Published by Elsevier B.V. All rights reserved,
Hybrid White Light-emitting Diodes by Organic-Inorganic materials
(2015)
Chen, K. J.
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Lai, Y. C.
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Lin, B. C.
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Lin, C. C.
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Chiu, S. H.
This study demonstrated the high uniformity hybrid white light-emitting didoes with polyfluoren (PFO) polymer and quantum dot (QD) with different CCT range from 3000K to 9000K.
Low subthreshold swing HfLaO/pentacene organic thin-film transistors
(2008-03-01)
Chang, M. R.
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Lee, P. T.
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McAlister, S. P.
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Chin, Albert
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電子工程學系及電子研究所
We have integrated a high-kappa HfLaO dielectric into pentacene-based organic thin-film transistors. We measured good device performance, such as a low subthreshold swing of 0.078 V/dec, a threshold voltage of - 1.3 V, and a field-effect mobility of 0.71 cm(2)/V.s. This occurred along with an ON-OFF state drive current ratio of 1.0 x 10(5), when the devices were operated at only 2 V. The performance is due to the high gate-capacitance density of 950 nF/cm(2) that is given by the HftaO dielectric, which is achieved at an equivalent oxide thickness of only 3.6 nm with a low leakage current of 5.1 x 10(-7) A/cm(2) at 2 V.
Low-Threshold-Voltage MoN/HfAlO/SiON p-MOSFETs With 0.85-nm EOT
(2009-08-01)
Chang, M. F.
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Lee, P. T.
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Chin, Albert
;
電子工程學系及電子研究所
;
光電工程學系
By using HfAlO as a capping layer on SiON, MoN/HfAlO/SiON p-MOSFETs show an effective work function of 5.1 eV, a low threshold voltage of -0.1 V, and a peak hole mobility of 80 cm(2)/(V . s) at small equivalent oxide thickness of 0.85 nm. These self-aligned and gate-first p-MOSFETs processes, with standard ion implantation and 1000 degrees C rapid thermal annealing, are fully compatible with current very large scale integration fabrication lines.
Performance enhancement of GaN-based flip-chip ultraviolet light-emitting diodes with a RPD AlN nucleation layer on patterned sapphire substrate
(2014-08-01)
Lin, B. C.
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Chiu, C. H.
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Lee, C. Y.
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Han, H. V.
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Tu, P. M.
In this work, flip-chip ultraviolet light-emitting diodes (FCUV-LEDs) on patterned sapphire substrate (PSS) at 375 nm were grown by an atmospheric pressure metal organic chemical vapor deposition (AP-MOCVD). A specialized reactive plasma deposited (RPD) AlN nucleation layer was utilized on the PSS to enhance the quality of the epitaxial layer. By using high-resolution X-ray diffraction, the full-width at half-maximum of the rocking curve shows that the FCUV-LEDs with RPD AlN nucleation layer had better crystalline quality when compared to conventional GaN nucleation samples. From the transmission electron microscopy (TEM) image, it can be observed that the tip and incline portion of the pattern was smooth using the RPD AlN nucleation layer. The threading dislocation densities (TDDs) are reduced from 7 x 10(7) cm(-2) to 2.5 x 10(7) cm(-2) at the interface between the u-GaN layers for conventional and AlN PSS devices, respectively. As a result, a much higher light output power was achieved. The improvement of light output power at an injection current of 20 mA was enhanced by 30%. Further photoluminescence measurement and numerical simulation confirm such increase of output power can be attributed to the improvement of material quality and light extraction. (C) 2014 Optical Society of America
Small-Subthreshold-Swing and Low-Voltage Flexible Organic Thin-Film Transistors Which Use HfLaO as the Gate Dielectric
(2009-02-01)
Chang, M. F.
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Lee, P. T.
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McAlister, S. P.
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Chin, Albert
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電子工程學系及電子研究所
Pentacene organic thin-film transistors (OTFTs) with a high-k HfLaO dielectric were integrated onto flexible polyimide substrates. The pentacene OTFTs exhibited good performance, such as a low subthreshold swing of 0.13 V/decade and a threshold voltage of -1.25 V. The field-effect mobility was 0.13 cm(2)/V . s at an operating voltage as low as only 2.5 V. These characteristics are attractive for high-switching-speed and low-power applications.
Super-high Density Si Quantum Dot Thin Film for Photovoltaic Properties Enhancement
(2013)
Kuo, K. Y.
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Huang, P. R.
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Chen, Y. J.
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Lee, P. T.
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光電工程學系
A gradient Si-rich oxide multilayer deposition structure is proposed to achieve super-high density Si quantum dot (QD) thin film while preserving QD size control ability for better photovoltaic properties.
Tunable nanoblock lasers and stretching sensors
(2016)
Lu, T. W.
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Wang, C.
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Hsiao, C. F.
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Lee, P. T.
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光電工程學系
Reconfigurable, reliable, and robust nanolasers with wavelengths tunable in the telecommunication bands are currently being sought after for use as flexible light sources in photonic integrated circuits. Here, we propose and demonstrate tunable nanolasers based on 1D nanoblocks embedded within stretchable polydimethylsiloxane. Our lasers show a large wavelength tunability of 7.65 nm per 1% elongation. Moreover, this tunability is reconfigurable and reliable under repeated stretching/relaxation tests. By applying excessive stretching, wide wavelength tuning over a range of 80 nm (spanning the S, C, and L telecommunication bands) is successfully demonstrated. Furthermore, as a stretching sensor, an enhanced wavelength response to elongation of 9.9 nm per % is obtained via the signal differential from two nanoblock lasers positioned perpendicular to each other. The minimum detectable elongation is as small as 0.056%. Nanoblock lasers can function as reliable tunable light sources in telecommunications and highly sensitive on-chip structural deformation sensors.