http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Ban, Keun-Yong,Kim, Yeongho,Kuciauskas, Darius,Bremner, Stephen P,Honsberg, Christiana B Institute of Physics 2016 Semiconductor science and technology Vol.31 No.12
<P>The optical properties of InAs quantum dots (QDs) embedded in a GaAsSb matrix with different delta (<I>δ</I>)-doping levels of 0, 2, 4, and 6 electrons per dot (e<SUP>−</SUP>/dot), incorporated to control the occupation of QD electronic states, are studied by photoluminescence (PL) spectroscopy. The time-resolved PL data taken at 10 K reveal that the increase of <I>δ</I>-doping density from 2 to 6 e<SUP>−</SUP>/dot decreases the recombination lifetime of carriers at ground states of the QDs from 996?±?36 to 792?±?19 ps, respectively. Furthermore, the carrier lifetime of the sample with 4 e<SUP>−</SUP>/dot is found to increase at a slower rate than that of the undoped sample as temperature increases above 70 K. An Arrhenius plot of the temperature dependent PL intensity indicates that the thermal activation energy of electrons in the QDs, required for carrier escape from the dot ground state to continuum state, is increased when the <I>δ</I>-doping density is high enough (>4 e<SUP>−</SUP>/dot). These results are attributed to the enhanced Coulomb interaction of electrons provided by the <I>δ</I>-doping, leading to reduced thermal quenching of the PL.</P>
Ban, Keun-Yong,Hong, Hyun-Gi,Noh, Do Young,Seong, Tae-Yeon,Song, June-O,Kim, Donghwan Institute of Physics 2005 Semiconductor science and technology Vol.20 No.9
<P>We have investigated indium-doped ZnO(IZO)/Ag Ohmic contacts to p-type GaN for use in UV-light-emitting diodes (LEDs). The as-deposited sample shows rectifying behaviour. However, the samples become Ohmic when annealed at temperature of 330–530 °C for 1 min in air. For example, the contact produces specific contact resistance of 5.51 × 10<SUP>−4</SUP> Ω cm<SUP>2</SUP> upon annealing at 530 °C. In addition, the 530 °C annealed IZO/Ag contacts give reflectance of 82.3% at a wavelength of 405 nm, which is better than that (70.6%) of the single Ag contacts. Near-UV LEDs fabricated with the IZO/Ag contacts give forward voltage of 3.24 V at an injection current of 20 mA, which is better than that with the single Ag contacts. On the basis of x-ray photoemission spectroscopy and scanning transmission electron microscopy results, possible Ohmic formation mechanisms are described.</P>
치과의원 환자들의 가철성 의치 사용에 대한 만족도 분석
반용석,송근배,정성화,조광헌 대한구강보건학회 2001 大韓口腔保健學會誌 Vol.25 No.1
The purposes of this study were to investigate the satisfaction of use of removable denture related to general, functional and esthetic factors among dental patients in the private dental clinics in Taegu, Korea and to establish the structure relationships of dental treatment satisfaction. Two hundred one patients who consented with this survey were selected and examined their anal status. Satisfaction degree was estimated by means of self-developed questionnaires, filled out by face-to-face interview. Collected data were analyzed by t-test, one-way ANOVA, chi-squared test, regression analysis and path analysis using statistical data analysis software SAS 6.12 and LISREL 8.12. The obtained results were as follows: 1. The satisfaction degree of four subscales was highest in esthetic factor(3.17±0.36), denture retention factor(3.10±0.60), general treatment satisfaction factor(2.94±0.56), and masticatory function factor(2.90±0.68) in descending order. It was appeared that patients were generally satisfied with all four factors. 2. By the result of multiple regression analysis, three subscales represented 35.5% of the variation of the general treatment satisfaction(R²=0.3535), and the satisfaction of masticatory function, denture retention and esthetic function had significant effect on the general treatment satisfaction. 3. On the comparison between proportion of denture satisfaction and satisfactions of subscales, as the satisfactions of general treatment, masticatory function and denture retention were increased, the proportion of denture satisfaction was significantly increased, but there was no significant relationship between the satisfaction of esthetic function and proportion of denture satisfaction. 4. The masticatory function factor, denture retention factor and general satisfaction of treatment factor were directly affected on the denture satisfaction, but esthetic factor was affected indirectly on the denture satisfaction as a result of path analysis.
Detection of the third transition of InAs/GaAsSb quantum dots
김영호,Keun-Yong Ban,Som N. Dahal,Heather McFelea,Christiana B. Honsberg 한양대학교 세라믹연구소 2016 Journal of Ceramic Processing Research Vol.17 No.4
The optical properties of InAs quantum dots (QDs) embedded in GaAs0.92Sb0.08 barriers have been studied. The samplesstudied consist of 20 multiple layers of InAs QDs embedded in GaAs0.92Sb0.08, with each QD/barrier system separated by a 100nm GaAs spacer. No appreciable changes in the QD properties, such as size, shape, and density, are observed by ScanningTransmission Electron Microscopy (STEM) images. The δ-doping plane beneath the InAs QDs allows the occupancy of theQD electronic sub-band states to be controlled. Low temperature (77 K) Fourier Transformation-Infrared Spectroscopy (FTIR)results, using a multiple internal reflection (MIR) technique to enhance the optical path length, show intersubbandabsorption in the InAs QD area. The broad peak observed around 240 meV corresponds to the energy separation between theelectron ground state and the continuum state of the QDs. Another broad peak around 440 meV is ascribed to a transitionbetween a deep level and shallow donor level due to δ-doping as the signal increases as the doping density increases. Bandstructure calculations using an eight band k·p method are used to confirm the experimental results observed here.