Browsing by Author "Lin, B. C."

Now showing 1 - 9 of 9

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.
Excellent Color Rendering Index Quantum Dots White Light-Emitting Diode with Distributed Bragg Reflector Structure
(2014)
Chen, K. J.
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Lin, B. C.
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Han, H. V.
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Lin, C. C.
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Lee, C. Y.
This study demonstrated the high CRI and excellent uniformity colloidal quantum dot white-light-emitting diodes with the DBR structure at different correlated color temperature from 2500 K to 4500K.
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.
Improved carrier injection in GaN-based VCSEL via AlGaN/GaN multiple quantum barrier electron blocking layer
(2015-10-19)
Hsieh, D. H.
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Tzou, A. J.
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Kao, T. S.
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Lai, F. I.
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Lin, D. W.
In this report, the improved lasing performance of the III-nitride based vertical-cavity surface-emitting laser (VCSEL) has been demonstrated by replacing the bulk AlGaN electron blocking layer (EBL) in the conventional VCSEL structure with an AlGaN/GaN multiple quantum barrier (MQB) EBL. The output power can be enhanced up to three times from 0.3 mW to 0.9 mW. In addition, the threshold current density of the fabricated device with the MQB-EBL was reduced from 12 kA/cm(2) (9.5 mA) to 10.6 kA/cm(2) (8.5 mA) compared with the use of the bulk AlGaN EBL. Theoretical calculation results suggest that the improved carrier injection efficiency can be mainly attributed to the partial release of the strain and the effect of quantum interference by using the MQB structure, hence increasing the effective barrier height of the conduction band. (C) 2015 Optical Society of America
Improved output power of GaN-based ultraviolet light-emitting diodes with sputtered AlN nucleation layer
(2015-03-15)
Chiu, C. H.
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Lin, Y. W.
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Tsai, M. T.
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Lin, B. C.
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Li, Z. Y.
In this work, the ultraviolet light emitting diodes (UV -LEDs) at 380 no were grown on patterned sapphire substrate (PSS) by atmospheric pressure metal organic chemical vapor deposition (AP-MOCVD). A sputtered 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 UV-LEDs with sputtered AlN nucleation layer had better crystalline quality when compared to conventional GaN nucleation samples. From the scanning electron microscope (SEM) and transmission electron microscopy (TEM) images, it can be observed that the Lip and sidewall portion of the pattern was smooth using the sputtered AlN nucleation layer. The threading dislocation densities (TDDs) are reduced from 6 x 107 cm(-2) to 2.5 x 107 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 povver was achieved. The light output power at an injection current of 20 mA was enhanced by 30%. Further photoluminescence (PL) measurement and numerical simulation confirm that this increase or output power can be attributed to the improvement of material quality and light extraction. (C) 2014 Elsevier B.V. All rights reserved.
Novel oxynitride layer applied to flash memory using HfO(2) as charge trapping layer
(2007)
Hsieh, C. R.
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Lai, C. H.
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Lin, B. C.
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Lou, J. C.
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Lin, J. K.
When the thickness of tunnel oxide layer is thinner than 7nm, the defects of tunnel oxide will form the leakage path easily. The trapped charges in trapping layer leak out through the leakage path and let we read the wrong data information. Therefore, the novel oxynitride process has been proposed to improve the reliabilities of Flash memory by reducing the interface states and bulk defects. Moreover, the novel oxynitride process is compatible with standard CMOS process today and it is practicable improvement in industry manufacturing. The HfO(2) layer was used as charge trapping layer. At first we found the better PDA conditions of HfO(2) film from the test capacitors and applied the optimum condition in integrated Flash memory devices. Finally, the complete electrical measurements and analysis were carried out. From the result of this study, the oxynitride can promote the reliabilities of Flash memory by improving the quality of tunnel oxide.
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
The minimum number of e-vertex-covers among hypergraphs with e edges of given ranks
(2009-01-06)
Chang, F. H.
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Fu, H. L.
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Hwang, F. K.
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Lin, B. C.
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應用數學系
We study the problem that among all hypergraphs with e edges of ranks l(1), ..., l(e) an v vertices, which hypergraph has the least number of vertex-covers of size e. The problem is very difficult and we only get some partial answers. We show an application of our results to improve the error-tolerance of a pooling design proposed in the literature. (c) 2008 Elsevier B.V. All rights reserved.