Browsing by Author "Huang, Yi-Hsin"

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3D structural construction of GaN-based light emitting diode by confocal micro-Raman spectroscopy
(2016-01-01)
Li, Heng
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Chang, Chiao-Yun
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Cheng, Hui-Yu
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Chen, Wei-Liang
;
Huang, Yi-Hsin
The key issue for light emission strength of GaN-based LEDs is the high defect density and strain in MQWs causing the electric polarization fields. In this work, we construct 3D confocal microspectroscopy to clarify strain distribution and the relationship between photoluminescence (PL) intensity and pattern sapphire substrate (PSS). From 3D construction of E-2(high) Raman and PL mapping, the dislocation in MQW can be traced to the cone tip of PSS and the difference in E-2(high) Raman mapping between substrate and surface is also measured. The ability to measure strain change in 3D structure nondestructively can be applied to explore many structural problems of GaN-based optoelectronic devices.
Application of Wearable Devices in Crime Scene Investigation and Virtual Reality
(2019-01-01)
Lee, Cheng-Lung
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Fang, Yuan
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Huang, Yi-Hsin
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Lee, Szu-Hao
;
Yeh, William Chen-Chung
In 2009, the United States National Academy of Sciences (NAS) proposed a list of suggestions to forensic-related issues, with emphasis on the correct use of modern technology to improve on-the-scene investigation. To ensure that the scene is fully detailed, a team of personnel including but not limited to photographer, videographer, evidence collector, and those who estimate and mark the scene are involved. However, traditional way of investigation not only utilizes too much manpower, but the destruction of crime scene is also an unavoidable problem we faced. Hence, the urgent tasks to be improved now are to protect, record and efficiently investigate the crime scene, to instantly deliver evidences for data matching, as well to provide an option to setup a video conference with experts in Forensics fields to assist officers on scene. The research integrates the concepts of "Wearable Devices" and "Forensic Cloud Computing", to showcase the benefits of Forensic database. Through cloud sharing, it is now possible to use portable devices for all on-the-scene records, video taking, and on-the-spot graphic detailing. Forensic Cloud is used with wireless and 3G/4G to deliver evidences and information. The user friendly design and mobile computing can be integrated together with instant communication and on-line forensic database. The research not only utilizes the latest technology to protect the integrity of crime scene, but will make a breakthrough in Crime Scene Investigation (CSI)-cost reduction in manpower, as well as enhancing the efficiency and effectiveness of investigation. Finally, with this research, we hope to strengthen scientific evidence, to push forward judiciary reformation, and to reduce the possibility of erroneous conviction.
Three dimensional characterization of GaN-based light emitting diode grown on patterned sapphire substrate by confocal Raman and photoluminescence spectromicroscopy
(2017-03-30)
Li, Heng
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Cheng, Hui-Yu
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Chen, Wei-Liang
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Huang, Yi-Hsin
;
Li, Chi-Kang
We performed depth-resolved PL and Raman spectral mappings of a GaN-based LED structure grown on a patterned sapphire substrate (PSS). Our results showed that the Raman mapping in the PSS-GaN heterointerface and the PL mapping in the InxGa1-xN/GaN MQWs active layer are spatially correlated. Based on the 3D construction of E2(high) Raman peak intensity and frequency shift, V-shaped pits in the MQWs can be traced down to the dislocations originated in the cone tip area of PSS. Detail analysis of the PL peak distribution further revealed that the indium composition in the MQWs is related to the residual strain propagating from the PSS-GaN heterointerface toward the LED surface. Numerical simulation based on the indium composition distribution also led to a radiative recombination rate distribution that shows agreement with the experimental PL intensity distribution in the InxGa1-xN/GaN MQWs active layer.
Three dimensional compressive strain and its effect on optical properties of GaN-based light emitting diode grown on patterned sapphire substrate by confocal spectromicroscopy
(2017-01-01)
Li, Heng
;
Cheng, Hui-Yu
;
Chen, Wei-Liang
;
Huang, Yi-Hsin
;
Li, Chi-Kang
We performed depth-resolved spectral mappings of GaN-based LED and results showed that the strain distribution propagating from PSS-GaN heterointerface toward surface and the PL intensity are spatially correlated. Numerical simulation based on indium composition distribution led to a radiative recombination rate distribution shows agreement with the experimental PL intensity distribution.