• 한국전기전자재료학회논문지
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• 제27권10호
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• pp.642-647
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• 2014

For feasible study of opto-electrical application regarding to oxide semiconductor, we implemented the N doped ZnO growth using a atomic layer deposition technique. The p-type ZnO deposition, necessary for ZnO-based optoelectronics, has considered to be very difficulty due to sufficiently deep acceptor location and self-compensating process on doping. Various sources of N such as $N_2$, $NH_3$, NO, and $NO_2$ and deposition techniques have been used to fabricate p-type ZnO. Hall measurement showed that p-type ZnO was prepared in condition with low deposition temperature and dopant concentration. From the evaluation of photoluminescence spectroscopy, we could observe defect formation formed by N dopant. In this paper, we exhibited the electrical and optical properties of N-doped ZnO thin films grown by atomic layer deposition with $NH_3OH$ doping source.

• 전기학회논문지
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• 제57권3호
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• pp.429-432
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• 2008

Much studies have been concentrated to develop the fabrication technique for high critical current density but still there are a lot of gap which should be overcome for large scale application of superconducting materials at liquid nitrogen temperature. The improvement of the critical current can be achieved by forming the nano size defect working as a flux pinning center inside the superconductor. In this paper, the establishment of fabrication condition and additive effects of second elements were examined so as to improve the related properties to the practical use of superconductor.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제42회 동계 정기 학술대회 초록집
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• pp.314-314
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• 2012

The dilute magnetic semiconductors (DMS) have been developed to multi-functional electro-magnetic devices. Specially, the Si based DMS formed by ion implantation have strong advantages to improve magnetic properties because of the controllable effects of carrier concentration on ferromagnetism. In this study, we investigated the deep level states of Fe- and Co-ions implanted Si wafer during rapid thermal annealing (RTA) process. The p-type Si (100) wafers with hole concentration of $1{\times}10^{16}cm^{-3}$ were uniformly implanted by Fe and Co ions at a dose of $1{\times}10^{16}cm^{-2}$ with an energy of 60 keV. After RTA process at temperature ranges of $500{\sim}900^{\circ}C$ for 5 min in nitrogen ambient, the Au electrodes with thickness of 100 nm were deposited to fabricate a Schottky contact by thermal evaporator. The surface morphology, the crystal structure, and the defect state for Fe- and Co- ion implanted p-type Si wafers were investigated by an atomic force microscopy, a x-ray diffraction, and a deep level transient spectroscopy, respectively. Finally, we will discuss the physical relationship between the electrical properties and the variation of defect states for Fe- and Co-ions implanted Si wafer after RTA.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
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• pp.420-420
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• 2013

We investigated oxygen plasma effect on defect states near the interface of AlGaN/GaN High Electron Mobility Transistor (HEMT) structure grown on a silicon substrate. After the plasma treatment, electrical properties were evaluated using a frequency dependant Capacitance-Voltage (C-V) and a temperature dependant C-V measurements, and a deep level transient spectroscopy (DLTS) method to study the change of defect densities. In the depth profile resulted from the temperature dependant C-V, a sudden decrease in the carrier concentration for two-dimensional electron gas (2DEG) nearby 250 K was observed. In C-V measurement, the interface states were improved in case of the oxygen-plasma treated samples, whereas the interface was degraded in case of the nitrogen-plasma treated sample. In the DLTS measurement, it was observed the two kinds of defects well known in AlGaN/GaN structure grown on sapphire substrate, which have the activation energies of 0.15 eV, 0.25 eV below the conduction band. We speculate that this defect state in AlGaN/GaN on the silicon substrate is caused from the decrease in 2DEG's carrier concentrations. We compared the various DLTS signals with filling pulse times to identify the characteristics of the newly found defect. In the filling pulse time range under the 80 us, the activation energies changed as the potential barrier model. On the other hand, in the filling pulse time range above the 80 us, the activation energies changed as the extended potential model. Therefore, we suggest that the found defect in the AlGaN/GaN/Si structure could be the extended defect related with AlGa/N/GaN interface states.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
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• pp.421-422
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• 2013

Recently, ZnO has received attentionbecause of its applications in optoelectronics and spintronics. In order to investigate deep level defects in ZnO, we used N-doped ZnO with various of the N-doping concentration. which are reference samples (undoped ZnO), 27%, 49%, and 88%-doped ZnO. Photoinduced current transient spectroscopy (PICTS) measurement was carried out to find deep level traps in high resistive ZnO:N. In reference ZnO sample, a deep trap was found to located at 0.31 (as denoted as the CO trap) eV below conduction band edge. And the CN1 and CN2 traps were located at 0.09, at 0.17 eV below conduction band edge, respectively. In the case of both annealed samples at 200 and $300^{\circ}C$, the defect density of the CO trap increases and then decreases with an increase of N-doping concentration. On the other hands, the density of CN traps has little change according to an increase of N-doping concentration in the annealed sample at $300^{\circ}C$. According to the result of PICTS measurement for different N-doping concentration, we suggest that the CO trap could be controled by N-doping and the CN traps be stabilized by thermal annealing at $300^{\circ}C$.

• 대한가정학회지
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• 제20권2호
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• pp.91-102
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• 1982

This study was designed to find out the nutritional defect of general Korean diet and the effective way of nutritional supplementation. Seventy weanling Sprague-Dawley male rats weighing 51.8$\pm$0.9g were blocked into ten groups and fed ten different diets ad libitum for eight weeks: Standard groups(st gp) was given 72% sugar-20% casein diet: Cereal-vegetable group(c-v gp) was fed cereal-vegetable diet(c-v diet) composed of rice, barley, soybean, spinach and cabbage: the other eight groups were fed c-v diets supplemented with casein, vitamin $B_{2}$, calcium, vitamin A, vitamin B2 and A, vitamin A and calcium, vitamin $B_{2}$ and calcium, vitamin A and $B_{2}$and calcium, respectively, on the basis of each nutrients content of standard diet. The results were as follows: 1. Food intakes and body weight gains in all the experimental groups were significantly lower than st gp. Among experimental groups, casein gp and vit B2 gp tended to gain more body weights than c-v gp. 2. Through all the experimental period, F.E.R., pp.E.R., and NDPcal% did nod show significant differences among all the experimental groups and st gp. 3. The weights of liver, kidney, and gastrocnemius were significantly lower in all the experimental groups as compared with st gp. But brain and sex organ weights did not show differences among all the groups. 4. Nitrogen contents of total carcass, liver, and gastrocnemius in all the experimental groups tended to be increased as compared with st gp, and among experimental groups, they tended to be increased by casein supplementation and decreased by ca supplementation. 5. Apparent nitrogen digestibility, urinary and fecal nitrogen excretion, the amount of nitrogen retained, and N.P.U. did not show any significant differences among all the groups. 6. Serum total protein concentrations did not show any significant differences among all the groups.

• 전기전자학회논문지
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• 제27권4호
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• pp.556-560
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• 2023

본 연구에서는 4H-SiC Epi Surface에 Nitrogen implantation 공정이 깊은준위결함과 lifetime에 미치는 영향을 비교분석하였다. Deep Level Transient Spectroscopy (DLTS)와 Time Resolved Photoluminescence (TR-PL)을 사용하여 깊은준위결함과 carrier lifetime을 측정하였다. As-grown SBD에서는 0.16 eV, 0.67 eV, 1.54 eV 에너지 준위와 implantation SBD의 경우 0.15 eV 준위에서의 결함을 측정되었으며, 이는 nitrogen implantation으로 불순물이 titanium 및 carbon vacancy를 대체됨으로 lifetime killer로 알려진 Z_1/2, EH_6/7 준위 결함은 감소하였다.

• 한국광물학회지
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• 제17권4호
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• pp.291-297
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• 2004

인은 다이아몬드 내에 함유될 수 있는 흥미로운 불순물 중의 하나로서 n 타입의 반도체가 될 수 있다는 점에서 흥미롭다. 그러므로 전기적 특성 및 광학적 특성이 많이 연구되고 있지만, 대부분이 CVD (화학 기상합성) 다이아몬드에 관한 것이다. 본 연구에서는 인을 첨가한 HPHT (고압과 고온) 다이아몬드를 합성하고 인이 어떻게 함유되는가 알아보기 위하여 CL 분광기로 광학적 특성을 살펴보았다. 그 결과, 기존에 발견된 발광피크(239 nm, 240～270 nm)뿐만 아니라 248, 603 nm에서 새로운 발광피크가 발견되었다. 이러한 발광피크들은 인과 같이 혼입된 질소나 붕소와 같은 불순물이 공존하여 발생한 복합 결함에 의한 것이라고 판단된다.

• Current Photovoltaic Research
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• 제11권3호
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• pp.87-95
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• 2023

As the demand for the Internet of Things grows, research into indoor photovoltaics for wireless power is becoming important. In particular, perovskite has attracted considerable attention due to its superior performance compared to other candidates. However, various surface defects present in perovskite are a limiting factor for high performance. In particular, deep-level surface defects caused by uncoordinated Pb²⁺ ions directly limit charge transport. In low light environments, this appears to be a more significant hurdle. In this study, ethylenediamine, which can provide covalent bonding to uncoordinated Pb²⁺ ions through nitrogen, was used as a surface treatment material for indoor photovoltaics. X-ray photoelectron spectroscopy confirmed that the uncoordinated Pb²⁺ ions were effectively passivated by the terminal nitrogen of ethylenediamine. As a consequence, a V_OC of 0.998 V, a JSC of 0.139 mA cm^-2 and a fill factor of 83.03% were achieved, resulting in an indoor photoelectric conversion efficiency of 38.02%.

• 한국결정성장학회지
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• 제13권1호
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• pp.31-35
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• 2003

PL data에 의해 다이아몬드가 HPHT(고온고압)으로 처리하는 과정을 거치면서 격자 내에 불순물 원자뿐만 아니라 공공과 침입형 원자의 움직임과 감소, 소멸, 생성 등으로 일부 격자가 재배열됨이 드러났다. 특히, PL spectrum은 Type IIa 다이아몬드가 가지는 매우 작은 양의 질소 불순물도 명확히 나타났으며, 이로 인해 상당한 수의 점결함이 결정 격자 내에 분산되어 있음을 알 수 있었다.