• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.27 no.10
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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.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.3
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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.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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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.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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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.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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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 $300^{\circ}C$.

• Journal of the Korean Home Economics Association
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• v.20 no.2
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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.

• Journal of IKEEE
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• v.27 no.4
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• pp.556-560
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• 2023

In this study, the impact of Nitrogen implantation process on deep-level defects and lifetime in 4H-SiC Epi surfaces was comparatively analyzed. Deep Level Transient Spectroscopy (DLTS) and Time Resolved Photoluminescence (TR-PL) were employed to measure deep-level defects and carrier lifetime. As-grown Schottky Barrier Diodes (SBDs) exhibited energy levels at 0.16 eV, 0.67 eV, and 1.54 eV, while for implantation SBD, defects at 0.15 eV were observed. This indicates a reduction in defects associated with energy levels Z_1/2 and EH_6/7, known as lifetime killers, as impurities from nitrogen implantation replace titanium and carbon vacancies.

• Journal of the Mineralogical Society of Korea
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• v.17 no.4
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• pp.291-297
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• 2004

Phosphorus is one of the interesting impurities in diamond, because it produces n-type semiconducting character. The character has been studied with spectroscopic methods as well as electric method, but most of the diamond used for these studies are conducted by the CVD (Chemical Vapor Deposition) diamond. In this study, we synthesized the phosphorus doped HPHT (High Pressure and High Temperature) diamond and investigated the characterization using CL spectroscopy to determine how phosphorus incorporated. As a result, the undocumented peaks of 248 and 603 nm as well as the reported peaks (239 nm, 240 ～ 270 nm) at the previous studies were observed. These luminescence peaks may be due to the complex defect of phosphorus with other impurities such as boron and nitrogen.

• Current Photovoltaic Research
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• v.11 no.3
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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%.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.13 no.1
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• pp.31-35
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• 2003

The PL data bases reveal the fact that a part of lattice of HPHT treated diamond is reconfigured by the reduction, elimination, generation, and movement of vacancies and interstitials as well as of impurity elements. In particular, this very sensitive method clearly illustrated that minute amount of nitrogen impurities is present in all of these type IIa diamonds, and reveal the presence of a considerable number of point defects dispersed throughout the crystal lattice.