• Journal of the Korean Institute of Telematics and Electronics
• /
• v.7 no.4
• /
• pp.14-19
• /
• 1970

Transient phenomena in the p-n junction due to the selfheating effect of microplasma current have been investigated for the cases of small current and of large current. For the small current case, the temperature rise of the microplasma site is proportional to the current decrease and a unique time constant could be defined. However, the situation was complicated for the case of large current, and the time constant was not uniquely defined.

• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.41 no.1
• /
• pp.9-14
• /
• 2004

In this paper, temperature dependence of effective ionization coefficient in Si is formulated as a single polynomial function of temperature, which allows analytical expressions for breakdown voltage of Si $p^+n$ junction as a function of temperature. The analytical breakdown voltages agree well with the simulation as well as the experimental ones reported within $3\%$ in error for the doping concentrations in the range of $10^{14}cm^{-3}{\~} 10^{17}cm^{-3}$ at 100K, 300K and 500K.

• Journal of the Korean Society of Combustion
• /
• v.4 no.2
• /
• pp.75-83
• /
• 1999

The effect of temperature distributions on soot volume fraction in double-concentric diffusion flames have been investigated experimentally. Using fine thermocouple wires and a rapid insertion mechanism, we have measured temperature without the effect of soot particles attached to the thermocouple junction, which can lower the temperature signal about 100 K by increasing the heat loss from the junction by radiation. The temperature at the flame axis is higher in the double-concentric diffusion flames than in normal co-flow diffusion flames because of the inverse diffusion flame. However, it is almost the same as that at the periphery of normal flames, on which the inverse flame does not have an effect. Thus, the lower soot concentration found in the double-concentric diffusion flame can be explained by the effect of nitrogen diffusion from the central air jet.

• The Transactions of the Korean Institute of Electrical Engineers C
• /
• v.48 no.4
• /
• pp.226-231
• /
• 1999

Temperature dependence of effective ionization coefficients in GaAs is formulated as a single polynomial function of temperature, which allows analytical expressions for breakdown voltage of GaAs $p^+n$ junctions as a function of temperature. At 300 K, extracted effective ionization coefficient of GaAs $p^+n$ junction especially agrees well with the published result of <111> oriented GaAs. The analytic results agree with the simulation as well as the experimental ones reported within 10% in error for the doping concentrations in the range of $10_{14}cm_{-3}~10_{17}cm_{-3}$ at 100 K, 300 K and 500 K.

• Bulletin of the Korean Chemical Society
• /
• v.30 no.1
• /
• pp.133-136
• /
• 2009

A newly designed Ag/$Ag^+$ reference electrode in a quartz tube with a tungsten tip junction (W-tip-Quartz- REF) was fabricated and its electrochemical performance was compared with a conventional Pyrex tube-based Ag/$Ag^+$ reference electrode (Py-REF). The results of the electrochemical potential measurements with the W-tip-Quartz- REF and the Py-REF in the LiCl-KCl eutectic melts for a wide temperature range proved that the oxide layer on the surface of the tungsten metal tip provided a high ionic conduction. Stability of our newly designed W-tip- Quartz-REF was tested by measuring a junction potential for 12 hours at 700${^{\circ}C}$. The results of the cyclic voltammetric measurement indicated that the Ag/$Ag^+$ reference electrode in the quartz tube with a tungsten tip junction can provide a good performance for a wide temperature range.

• Journal of the Korean Institute of Telematics and Electronics A
• /
• v.32A no.2
• /
• pp.89-95
• /
• 1995

The structure of boron ion-implanted pn junctio in the vacancy-doped p-type HgCdTe was investigated with the differential Hall measurement. The as-implanted junction showed the electron concentration as high as 1${\times}10^{18}/cm^{3}$ and the junction depth of 0.6.mu.m. When the HgCdTe junction was heated in oven, the electron concentration near the junction decreased and the junction depth increased as the annealing temperature and time increased. The junction structure after the thermal annealing was n$^{+}$/n$^{-}$/p. For the 200.deg. C 20min annealed sample, the electron mobility was 10$^{4}cm^{2}/V{\cdot}$s near the surface(n$^{+}$), and was larger thatn 10$^{5}cm^{2}/V{\cdot}$s near the junction(n$^{+}$). The junction formation mechanism is conjectured as follows. When HgCdTe is ion-implanted, the ion energy generates crystal defecis and displaced Hg atoms HgCdTe is ion-implanted, the ion energy generates crystal defecis and displaced Hg atoms near the surface. The displaced Hg vacancies diffuse in easily by the thernal treatment and a fill the Hg vacancies in the p-HgCdTe substrate. With the Hg vacancies filled completely, the GfCdTe substrate becomes n-type because of the residual n-type impurity which was added during the wafer growing. Therefore, the n$^{+}$/n$^{-}$/p regions are formed by crystal defects, residual impurities, and Hg vacancies, respectively.

• 한국신재생에너지학회:학술대회논문집
• /
• 2005.06a
• /
• pp.196-200
• /
• 2005

In this work, we investigated simple Aㅣ/TCO/a-Si:H(n)/c-Si(p)/Al hetero-junction solar cells prepared by low temperature processes, unlike conventional thermal diffused c-Si solar cells. a-Si:H/c-Si hetero-junction solar cells are processed by low temperature deposition of n-type hydrogenated amorphous silicon (a-Si:H) films by plasma-enhanced chemical vapor deposition on textured and flat p-type silicon substrate. A detailed investigation was carried out to acquire optimization and compatibility of amorphous layer, TCO (ZnO:Al) layer depositions by changing the plasma process parameters. As front TCO and back contact, ZnO:Al and AI were deposited by rf magnetron sputtering and e-beam evaporation, respectively. The photovoltaic conversion efficiency under AMI.5 and the quantum efficiency on $1cm^2$ sample have been reported. An efficiency of $12.5\%$ is achieved on hetero-structure solar cells based on p-type crystalline silicon.

• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.44 no.5
• /
• pp.42-49
• /
• 2007

This paper introduces a study on reliability-driven device placement using simulated annealing algorithm which can be applicable to MCM or electronic systems embedded in a spacecraft running at thermal conduction environment. Reliability of the unit's has been predicted with the devices' junction temperatures calculated from FDM solver and optimized by simulated annealing algorithm. Simulated annealing in this paper adopts swapping devices method as a perturbation. This paper describes and compares the optimization simulation results with respect to two objective functions: minimization of failure rate and minimization of average junction temperature. Annealing temperature variation simulation case and equilibrium coefficient variation simulation case are also presented at the two respective objective functions. This paper proposes a new approach for reliability optimization of MCM and electronic systems considering those simulation results.

• Journal of Broadcast Engineering
• /
• v.21 no.5
• /
• pp.816-823
• /
• 2016

This paper studies a light emitting diode(LED) overlapping method of a head-up display that consists of a digital micro device(DMD) panel and a red, green, blue LED in order to increase the brightness of display system and optical output power. This optimization overlapping method removes a quantization noise which occur due to LED overlapping too excessive and stabilizes the junction temperature of LED. In order to reduce junction temperature of LED, the a correlation between a green duty and LED overlapping ratio is studied. Throughout this study, the brightness of head-up display exhibited high increasement ratio of luminance around 33.3 percent at 39 percent overlapping method.

• Journal of Information Display
• /
• v.13 no.1
• /
• pp.37-42
• /
• 2012

An empirical functional form was suggested for the analysis of the emission spectrum of high-power light-emitting diode (LED) consisting of a sharp blue peak from the LED chips and a broad yellow peak from the phosphor layer. The peak positions, half widths, shape parameters, and amplitudes of these two peaks were reliably obtained as a function of the temperature, and the results were discussed qualitatively in relation with the junction temperature. The adoption of an inert liquid was found to have significantly reduced the LED temperature and the color shift of the emitted light. The phenomenological approach used in this study may be helpful in the simulation of the LED spectrum under various thermal conditions, and may thus be helpful in the improvement of the device performance.