• Journal of Mechanical Science and Technology
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• v.17 no.12
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• pp.2099-2106
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• 2003

In this paper, a novel fast response NDIR analyzer (FRNDIR), which uses an electrically pulsed semiconductor emitter and dual type PbSe detector for the PPM-level detection of carbon dioxide (CO$_2$) at a wavelength of 4.28 $\mu\textrm{m}$, is described. Modulation of conventional NDIR energy typically occurs at 1 to 20 Hz. To achieve real time high-speed measurement, the new analyzer employs a semiconductor light emitter that can be modulated by electrical chopping. Updated measurements are obtained every one millisecond. The detector has two independent lead selenide (PbSe) with IR band pass filters. Both the emitter accuracy and the detector sensitivity are increased by thermoelectric cooling of up to -20 degrees C in all semiconductor devices. Here we report the use of semiconductor devices to achieve improved performance such that these devices have potential application to CO$_2$ gas measurement and, in particular, the measurement of fast response CO$_2$ concentration at millisecond level.

• ETRI Journal
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• v.33 no.5
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• pp.810-813
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• 2011

We report the use of a widely tunable detuned dual-mode laser diode (DML) as a compact and portable continuous-wave THz emitter. The wavelength difference between the two lasing modes of this DML can be tuned from 2.4 nm to 9.3 nm by using integrated microheaters. The power difference between these modes is less than 1 dB, and the side-mode suppression ratio is greater than 30 dB over the entire tuning range.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.48 no.7
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• pp.530-532
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• 1999

A new lateral device entitled SB-DCEST(segmented p-base dual-channel emitter switched thyristor), which suppresses the snapback is proposed and successfully fabricated. The proposed device effectively suppressed the snapback phenomenon by employing the gigh resistance in self-aligned segmented p-base when compared with the conventional DCEST. The experimental results show that the SB-DCEST has the low forward voltage drop of 4.3 V at anode current of $150 A/cm^2$ with the eliminated snap-back regime, while conventional DCEST exhibits higher forward voltage drop of 5.3 V.

• IEIE Transactions on Smart Processing and Computing
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• v.4 no.5
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• pp.318-323
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• 2015

We present a new way to create a thermally stable, highly strained germanium (Ge) optical resonator using a novel Ge-on-dual-insulators substrate. Instead of using a conventional way to undercut the oxide layer of a Ge-on-single-insulator substrate for inducing tensile strain in germanium, we use thin aluminum oxide as a sacrificial layer. By eliminating the air gap underneath the active germanium layer, we achieve an optically insulating, thermally conductive, and highly strained Ge resonator structure that is critical for a practical germanium laser. Using Raman spectroscopy and photoluminescence experiments, we prove that the novel geometry of our Ge resonator structure provides a significant improvement in thermal stability while maintaining good optical confinement.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.23 no.3
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• pp.183-189
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• 2010

In this paper, the trench gate emitter switched thyristor(EST) withl trench gate electrode is proposed for improving snap-back effect which leads to a lot of problems in device applications. The parasitic thyristor which is inherent in the conventional EST is completely eliminated in this structure, allowing higher maximum controllable current densities for ESTs. The dual trench gate allows homogenous current distribution in the EST and preserves the unique feature of the gate controlled current saturation of the thyristor current. The characteristics of the 1700 V forward blocking EST obtained from two-dimensional numerical simulations (MEDICI) is described and compared with that of a conventional EST. we carried out layout, design and process of EST devices.

• ETRI Journal
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• v.38 no.4
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• pp.665-674
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• 2016

We designed and fabricated a semiconductor optical amplifier-integrated dual-mode laser (SOA-DML) as a compact and widely tunable continuous-wave terahertz (CW THz) beat source, and a pin-photodiode (pin-PD) integrated with a log-periodic planar antenna as a CW THz emitter. The SOA-DML chip consists of two distributed feedback lasers, a phase section for a tunable beat source, an amplifier, and a tapered spot-size converter for high output power and fiber-coupling efficiency. The SOA-DML module exhibits an output power of more than 15 dBm and clear four-wave mixing throughout the entire tuning range. Using integrated micro-heaters, we were able to tune the optical beat frequency from 380 GHz to 1,120 GHz. In addition, the effect of benzocyclobutene polymer in the antenna design of a pin-PD was considered. Furthermore, a dual active photodiode (PD) for high output power was designed, resulting in a 1.7-fold increase in efficiency compared with a single active PD at 220 GHz. Finally, herein we successfully show the feasibility of the CW THz system by demonstrating THz frequency-domain spectroscopy of an ${\alpha}$-lactose pellet using the modularized SOA-DML and a PD emitter.

• Transactions on Electrical and Electronic Materials
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• v.4 no.2
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• pp.15-19
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• 2003

In this paper, the new dual trench gate Emitter Switched Thyristor (DTG-EST) is proposed for improving snap-back effect which leads to a lot of serious problems of device applications. Also the parasitic thyristor that is inherent in the conventional EST is completely eliminated in this structure, allowing higher maximum controllable current densities for ESTs. The conventional EST exhibits snap-back with the anode voltage and current density 2.73V and 35A/$\textrm{cm}^2$, respectively. But the proposed DTG-EST exhibits snap-back with the anode voltage and current density 0.96V and 100A/$\textrm{cm}^2$, respectively.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.53 no.7
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• pp.358-363
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• 2004

A new 600 V dual gate transistor employing thyristor action, which incorporates floating PN junction and trench gate IGBT, is proposed to improve the forward current-voltage characteristics and the short circuit ruggedness. Our two-dimensional numerical simulation shows that the proposed device exhibits low forward voltage drop and eliminates the snapback phenomena compared with conventional trench gate IGBT and EST The proposed device achieves high current saturation characteristics by separating floating N+ emitter and cathode. The proposed device achieves low saturation current value compared with conventional devices, and the short-circuit ruggedness is improved. The proposed device may be suitable for the use of high voltage switching applications.

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08b
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• pp.1411-1414
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• 2007

We have developed a top-emitting white organic electroluminescent device (TWOLED) incorporating a low-reflectivity molybdenum (Mo) anode and doped transport layers as well as a dual-layer architecture of doped blue and yellow emitters with the same blue host. The EL efficiency and operational lifetime of TWOLED can be enhanced by a factor of 1.2 and 3.4 than that of standard TWOLED, respectively, with a co-doping technology in yellow emitter by doping another blue dopant. The enhancement in device performances can be attributed to improve the energy transfer efficiency from blue host to yellow dopant through a blue dopant as medium in yellow emitter.

• 한국컴퓨터산업교육학회:학술대회논문집
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• 2003.11a
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• pp.71-74
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• 2003

A vertical trench electrode type EST has been proposed in this paper. The proposed device considerably improve the snap-back effect which leads to a lot of problem of device applications. In this paper, the vertical dual gate Emitter Switched Thyristor(EST) with trench electrode has been proposed for improving snap-back effect. It is observed that the forward blocking voltage of the proposed device is 800V. The conventional EST of the same size were no more than 633V. Because the proposed device was constructed of trench-type electrode, the electric field moved toward trench-oxide layer, and the punch through breakdown of the proposed EST is occurred at latest.