Current–voltage–temperature (I–V–T) characteristics of Pd/Au Schottky contacts on n-InP (111)

M. Bhaskar Reddy,A. Ashok Kumar,V. Janardhanam,V. Rajagopal Reddy,P. Narasimha Reddy 한국물리학회 2009 Current Applied Physics Vol.9 No.5

We have investigated the current–voltage–temperature (I–V–T) characteristics of Pd/Au/InP Schottky barrier diodes in the temperature range of 220–400 K. The I–V analysis based on thermionic emission (TE) theory shows an abnormal decrease of apparent barrier height and increase of ideality factor at low temperatures. The conventional Richardson plot exhibits nonlinearity with activation energy of 0.17 eV and the Richardson constant value of 5.63 × 10-6 A cm-2 K-2. The nonlinearity in the Richardson plot and strong dependence of Schottky barrier parameters on temperature may be attributed to the spatial inhomogeneity in the interface. Further, the homogeneous barrier height has been obtained from the linear relationship between experimentally obtained effective barrier heights and ideality factors. Φb versus (2kT)-1 plot has been drawn to obtain the mean barrier height [Φbo(T = 0 K)] and the standard deviation (σs) at zero-bias which are found to be 0.84 eV, 138 meV, respectively. The series resistance is also estimated from the forward current–voltage characteristics of Pd/Au/InP Schottky contacts using Cheung’s method and found that it is strongly dependent on temperature and also decreases with increase in temperature. We have investigated the current–voltage–temperature (I–V–T) characteristics of Pd/Au/InP Schottky barrier diodes in the temperature range of 220–400 K. The I–V analysis based on thermionic emission (TE) theory shows an abnormal decrease of apparent barrier height and increase of ideality factor at low temperatures. The conventional Richardson plot exhibits nonlinearity with activation energy of 0.17 eV and the Richardson constant value of 5.63 × 10-6 A cm-2 K-2. The nonlinearity in the Richardson plot and strong dependence of Schottky barrier parameters on temperature may be attributed to the spatial inhomogeneity in the interface. Further, the homogeneous barrier height has been obtained from the linear relationship between experimentally obtained effective barrier heights and ideality factors. Φb versus (2kT)-1 plot has been drawn to obtain the mean barrier height [Φbo(T = 0 K)] and the standard deviation (σs) at zero-bias which are found to be 0.84 eV, 138 meV, respectively. The series resistance is also estimated from the forward current–voltage characteristics of Pd/Au/InP Schottky contacts using Cheung’s method and found that it is strongly dependent on temperature and also decreases with increase in temperature.

농업용 붐 분무기의 노즐 높이 및 분무 균일 성 측정을 위한 초음파 센서에 대한 온도의 영향

샤피크키라가 ( Shafik Kiraga ),레자나심 ( Md Nasim Reza ),초두리밀런 ( Milon Chowdhury ),이슬람나피울 ( Md Nafiul Islam ),정선옥 ( Sun-ok Chung ) 한국농업기계학회 2021 한국농업기계학회 학술발표논문집 Vol.26 No.1

The increasing popularity of boom height controllers requires a desired nozzle height above the spray targets for effective spraying. The objective of this study was to determine the effect of temperature on nozzle height measurement using ultrasonic sensors and the impact on spray uniformity. Experiments were carried out with a constant nozzle spacing of 50 cm and a pressure of 600 kPa considering temperature compensation and non-compensation states of ultrasonic sensor measurements. Nozzle heights of 30, 50, and 70 cm were selected for reference. Two measurements were carried out for each selected height with a temperature compensated and non-compensated state at 15, 25, and 300C. The spray distribution was also determined for each measurements. Coefficient of Variation (CV) and percent measurement error (ME) were used to characterize spray uniformity and temperature effect on height measurement. The estimated heights with temperature compensation were closer to the reference heights, which exhibits a low ME. The ME increased from low to high temperatures. Temperature compensated heights resulted in more even spraying trends, with lower CV values accompanied by non-compensated heights. Our findings showed that, ultrasonic sensors need temperature correction for proper Nozzle height measurement and optimal spray distribution.

Detection of Temperature Stress Using Chlorophyll Fluorescence Parameters and Stress-related Chlorophyll and Proline Content in Paprika (Capsicum annuum L.) Seedlings

Shiva Ram Bhandari,Yong Hyeon Kim,Jun Gu Lee 한국원예학회 2018 원예과학기술지 Vol.36 No.5

Thirty three-day-old paprika (Capsicum annuum L.) seedlings were grown under different temperature conditions (low: 10°C, moderate: 25°C, and high: 35°C) in a closed plant production system for 32 days and their chlorophyll (Chl) fluorescence and growth parameters, and Chl and proline contents were measured at 0, 1, 2, 4, 8, 16, 24, and 32 days after the initiation of treatment. Minimal fluorescence (F0) sharply increased from 8 days and continued until the end of the experimental period under all three temperature treatments, with the highest increase at the low temperature condition. Maximum quantum yield (Fv/Fm) and the efficiency of excitation capture of open photosystem II (PSII) center (F’v/F’m) significantly decreased at low temperature compared with those at moderate and high temperatures. Non-photochemical quenching (NPQ) and the ratio of the fluorescence decrease (Rfd) were significantly affected, particularly at the high temperature, followed by the low and moderate temperatures; quantum yield of non-regulated energy dissipation in PSII (ϕNO) increased under all treatments. Furthermore, Chl content showed a relatively greater decrease at the low temperature compared to the high temperature throughout the experiment; moderate temperature showed a stable chlorophyll content throughout the experiment. Proline concentration increased significantly at the high and low temperatures, but not under moderate temperature. Plant height and shoot and root weight were the lowest at the low temperature. Overall, our results suggest that paprika plants were more severely affected by low temperature than high temperature with respect to photosynthetic activity as well as growth, which was significantly slowed at low temperature.

고층건축물의 높이에 따른 대류열전달률이 실내표면결로에 미치는 영향에 관한 이론적 연구

김태영(Tae Young Kim),조성우(Sung Woo Cho) 대한설비공학회 2022 설비공학 논문집 Vol.34 No.1

Although the temperature coefficient between outdoor air temperature and indoor air temperature is used to determine whether condensation occurs, it is reasonable to predict surface condensation using the surface temperature difference between outdoor and indoor. This study is conducted to determine whether condensation occurs by not using the air temperature difference between indoor and outdoor (the existing methods) but by applying the surface temperature difference between indoor and outdoor surfaces. The outdoor surface temperature is affected by air velocity on the building height, thus the convection heat transfer coefficient is different depending on the building height. The indoor surface temperature distribution is 21.4℃~21.5℃ when the existing equation is applied. But by applying the proposed equation, the indoor surface temperature distribution for the lower floor is 13.0~17.8℃, for the middle floor is 12.3℃~ 17.1℃, and for the top floor is 12.0℃~16.8℃. As the indoor surface temperature can be lower than indoor air dew point temperature, surface condensation is possible.

태양열 온풍기내부의 집열면 조건이 덕트 출구공기의 온도상승에 미치는 영향

고동국 한국기계기술학회 2015 한국기계기술학회지 Vol.17 No.3

This paper analyzed the increasing air temperature at outlet according to condition of absorber plate of the solar air heater. Effects on the increasing air temperature at outlet of duct according to absorber plate temperature were analyzed by using numerical analysis technique. And also the effects of the height and position of absorber plate on increasing temperature at outlet were analysed. As the results, Outlet air temperature was small influenced in velocity 5m/s of inlet according to absorber plate temperature. And the highest outlet average temperature distribution appeared at the height of 2cm and the bottom absorber plate of duct at the inlet aspect ratio 2.

중성자 조사된 SiC Schottky Diode의 온도 의존 특성

김성수,구상모,Kim, Sung-Su,Koo, Sang-Mo 한국전기전자재료학회 2014 전기전자재료학회논문지 Vol.27 No.10

The temperature dependent characteristics on the properties of SiC Schottky Diode has been investigated. In this study, the temperature dependent current-voltage characteristics of the SiC Schottky diode were measured in the range of 300 ~ 500 K. Divided into pre- and post- irradiated device was measured. The barrier height after irradiation device at 500 K increased 0.15 eV compared to 300 K, the barrier height of pre- neutron irradiated Schottky diode increased 0.07 eV. The effective barrier height after irradiation increased from 0.89 eV to 1.05 eV. And ideality factor of neutron irradiated Schottky diode at 500 K decreased 0.428 compared to 300 K, the ideality factor of pre- neutron irradiated Schottky diode decreased 0.354. Also, a slight positive shift in threshold voltage from 0.53 to 0.68 V. we analyzed the effective barrier height and ideality factor of SiC Schottky diode as function of temperature.

횡단 공기유동장으로 분사되는 저온 에탄올 제트의 침투거리

이종권 ( Jongkwon Lee ),구자예 ( Jaye Koo ) 한국분무공학회지 2020 한국액체미립화학회지 Vol.25 No.2

The jet in crossflow is a spray method used in the various air-breathing engine. In order to understand the spray characteristics in various environments, many prior studies have been conducted. However, there is a lack of understanding of the low-temperature liquid spray characteristics below 273 K. With this in mind, we tried to enhance the knowledge of the lowtemperature liquid spray characteristics by identifying the penetration height of low-temperature ethanol. The experiment was conducted under phase pressure, and 273 K of air and 293, 263, and 233 K of ethanol was used. Shadowgraphy was employed to measure the liquid penetration, and Otsu’s method was used to analyze the penetration height. The heights tend to decrease as the temperature of the liquid jet decreases. A correlation for the penetration height in the experimental conditions was derived and presented.

Modeling of step height reduction with temperature function in copper CMP

Yeongil Shin,정종민,Youngwook Park,Seonho Jeong,Hokyoung Jung,정해도 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.12

Chemical mechanical polishing (CMP) is a global planarization process that effectively reduces the step height of patterns. Conventional mathematical models for predicting step height reduction in oxide CMP have been successful; however, a relatively large error is obtained when applied to copper CMP because of the effects of chemical factors on copper removal rate. This study focuses on temperature as a parameter and develops a modified semi-empirical model that considers its effects. The temperature function was obtained using experiments that measured the copper etching and removal amounts according to the temperature. The developed copper model had an error rate of less than 10 %, whereas the oxide model had an error rate of approximately 30 %, indicating that the model with temperature consideration is more effective in predicting copper CMP results.

태양열 온풍기내부의 집열면 조건이 덕트 출구 공기의 온도에 미치는 영향

고동국 한국기계기술학회 2015 한국기계기술학회지 Vol.17 No.3

This paper analyzed air temperatures at outlet according to condition of absorber plate of the solar air heater. Effects on air temperature at outlet of duct according to absorber plate temperature were analyzed by using numerical analysis technique. And also the effects on air temperatures at outlet were analysed by the height and position of absorber plate. As the results, air temperatures at outlet of duct was small influenced in velocity 5 m/s of inlet according to absorber plate temperature. And the highest outlet average temperature distribution appeared at the height of 2 cm and the bottom absorber plate of duct at the inlet aspect ratio 2.

동축류 제트에서 초기 온도 변화에 따른 층류 부상화염

김길남(Kil Nam Kim),원상희(Sang Hee Won),정석호(Suk Ho Chung) 대한기계학회 2005 대한기계학회 춘추학술대회 Vol.2005 No.5

Characteristics of laminar lifted flames for highly diluted propane with nitrogen have been investigated in various initial temperatures, especially in high temperature. Liftoff height and liftoff velocity are investigated for various fuel mole fraction and initial temperature. The liftoff height decreases as fuel mole fraction and initial temperature increase, and it can be correlated well with laminar burning velocity although the increasing slope of liftoff height is differ from initial temperature and fuel mole fraction. These results show that lifted flames are stabilized based on the balance mechanism regardless of its initial temperature up to 900K. Liftoff phenomenon can be observed for smaller jet velocity than laminar burning velocity in ambient temperature, and it can be attributed to the effect of buoyancy. When the effect of buoyancy diminishes, Ri < 0.1, non-dimensional liftoff velocity, (ReRi)?¹ is correlated well with stoichiometric laminar burning velocity.