• Title/Summary/Keyword: Quantum dot LED

Search Result 33, Processing Time 0.031 seconds

A Study on the III-nitride Light Emitting Diode with the Chip Integration by Metal Interconnection (금속배선 칩 집적공정을 포함하는 질화물 반도체 LED 광소자 특성 연구)

  • 김근주;양정자
    • Journal of the Semiconductor & Display Technology
    • /
    • v.3 no.3
    • /
    • pp.31-35
    • /
    • 2004
  • A blue light emitting diode with 8 periods InGaN/GaN multi-quantum well structure grown by metal-organic chemical vapor deposition was fabricated with the inclusion of the metal-interconnection process in order to integrate the chips for light lamp. The quantum well structure provides the blue light photoluminescence peaked at 479.2 nm at room temperature. As decreasing the temperature to 20 K, the main peak was shifted to 469.7 nm and a minor peak at 441.9 nm appeared indicating the quantum dot formation in quantum wells. The current-voltage measurement for the fabricated LED chips shows that the metal-interconnection provides good current path with ohmic resistance of 41 $\Omega$.

  • PDF

In Vitro Quantum Dot LED to Inhibit the Growth of Major Pathogenic Fungi and Bacteria in Lettuce (Quantum Dot LED를 이용한 상추 주요 병원성 곰팡이 및 세균의 생장억제효과 기내실험)

  • Lee, Hyun-Goo;Kim, Sang-Woo;Adhikari, Mahesh;Gurung, Sun Kumar;Bazie, Setu;Kosol, San;Gwon, Byeong-Heon;Ju, Han-Jun;Ko, Young-Wook;Kim, Yong-Duk;Yoo, Yong-Whan;Park, Tae-Hee;Shin, Jung-Chul;Kim, Min-Ha;Lee, Youn Su
    • Research in Plant Disease
    • /
    • v.25 no.3
    • /
    • pp.114-123
    • /
    • 2019
  • QD LED has an ideal light source for growing crops and can also be used to control plant pathogenic microorganisms. The mycelial growth inhibition effect of QD LED light on Rhizoctonia solani, Phytophthora drechsleri, Sclerotinia sclerotiorum, Sclerotinia minor, Botrytis cinerea, Fusarium oxysporum, Pectobacterium carotovorum, and Xanthomonas campestris were investigated. According to the results, BLUE (450 nm) light, suppressed S. sclerotiorum by 16.7% at 50 cm height from the light source, and 94.1% mycelial growth at 30 cm height. Mycelial growth of Sclerotinia minor was inhibited by 80.4% at 50 cm height and 36.3% at 50 cm height in B. cinerea. S. minor, and B. cinerea was inhibited by 100% mycelial growth at a height of 30 cm from the light source. At 15 cm height, all three pathogens (B. cinerea, S. minor, and S. sclerotiorum) was inhibited by 100%. QD RED (M1) and QD RED (M2) light suppressed mycelial growth of S. minor and B. cinerea by 100% at 30 cm and 15 cm height from the light source. For S. sclerotiorum, QD RED (M1) and QD RED (M2) showed 75.2% and 100% inhibition, respectively. Further experiment was conducted to know the suppression effect of lights after inoculating the fungal pathogens on lettuce crop. According to the results, QD RED (M2) suppressed the S. sclerotiorum by 59.9%. In addition, Blue (450 nm), QD RED (M1), and QD RED (M2) light reduce the infestation by 59.9%. In case of B. cinerea, disease reduction was found 84% by BLUE (450 nm) light. Results suggest that the growth inhibition of mycelium increases by Quantum dot LED light.

Technology Development Trends of Cesium Lead Halide Based Light Emitting Diodes (세슘납할로겐화물 페로브스카이트 기반 LED 기술개발 동향)

  • Pyun, Sun Ho
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
    • /
    • v.29 no.12
    • /
    • pp.737-749
    • /
    • 2016
  • Recently perovskite materials with much cheaper cost and marvellous optoelectronic properties have been studied for next generation LED display devices overseas. Technology development trends of inorganic $CsPbX_3$(X=halogen) based LEDs (PeLEDs) with assumed high stability were investigated on literature worldwide. It was found that syntheses methods of these nanocrystals (NCs, mainly quantum dots, QDs) made great progress. A new room temperature synthesis method showed outstanding PL (photoluminescence) properties such as high quantum yield (QY), narrow emission width, storage stability comparable with, or often exceeding those of conventional hot injection method and CdSe@ZnS type inorganic colloidal QDs. PeLEDs with shell layers might be more promising, indicating urgent real research start of this solution processing technology for small businesses in Korea.

Inorganic Phosphor Materials for White LED Display (백색 엘이디 디스플레이를 위한 형광체 재료 기술)

  • Lee, Jung-Il;Ryu, Jeong Ho
    • Journal of Institute of Convergence Technology
    • /
    • v.4 no.1
    • /
    • pp.21-27
    • /
    • 2014
  • White LEDs (light-emitting diodes) are promising new-generation light sources which can replace conventional lamps due to their high reliability, low energy consumption and eco-friendly effects. This paper briefly reviews recent progress of oxy/nitride host phosphor and quantum dot materials with broad excitation band characteristics for phosphor-converted white LEDs. Among oxy/nitride host materials, $M_2Si_5N_8:Eu^{2+}$, $MAlSiN_3:Eu^{2+}$ M-SiON(M=Ca, Sr, Ba), ${\alpha}/{\beta}-SiAlON:Eu^{2+}$ are excellent phosphors for white LED using blue-emitting chip. They have very broad excitation bands in the range of 440-460 nm and exhibit emission from green to red. In this paper, In this review we focus on recent developments in the crystal structure, luminescence and applications of the oxy/nitride phosphors for white LEDs. In addition, the application prospects and current trends of research and development of quantum dot phosphors are also discussed.

Fabrication of Silicon Quantum Dots in Si3N4 Matrix Using RF Magnetron Co-Sputtering (RF 마그네트론 코스퍼터링을 이용한 Si3N4 매트릭스 내부의 실리콘 양자점 제조연구)

  • Ha, Rin;Kim, Shin-Ho;Lee, Hyun-Ju;Park, Young-Bin;Lee, Jung-Chul;Bae, Jong-Seong;Kim, Yang-Do
    • Korean Journal of Materials Research
    • /
    • v.20 no.11
    • /
    • pp.606-610
    • /
    • 2010
  • Films consisting of a silicon quantum dot superlattice were fabricated by alternating deposition of silicon rich silicon nitride and $Si_3N_4$ layers using an rf magnetron co-sputtering system. In order to use the silicon quantum dot super lattice structure for third generation multi junction solar cell applications, it is important to control the dot size. Moreover, silicon quantum dots have to be in a regularly spaced array in the dielectric matrix material for in order to allow for effective carrier transport. In this study, therefore, we fabricated silicon quantum dot superlattice films under various conditions and investigated crystallization behavior of the silicon quantum dot super lattice structure. Fourier transform infrared spectroscopy (FTIR) spectra showed an increased intensity of the $840\;cm^{-1}$ peak with increasing annealing temperature due to the increase in the number of Si-N bonds. A more conspicuous characteristic of this process is the increased intensity of the $1100\;cm^{-1}$ peak. This peak was attributed to annealing induced reordering in the films that led to increased Si-$N_4$ bonding. X-ray photoelectron spectroscopy (XPS) analysis showed that peak position was shifted to higher bonding energy as silicon 2p bonding energy changed. This transition is related to the formation of silicon quantum dots. Transmission electron microscopy (TEM) and electron spin resonance (ESR) analysis also confirmed the formation of silicon quantum dots. This study revealed that post annealing at $1100^{\circ}C$ for at least one hour is necessary to precipitate the silicon quantum dots in the $SiN_x$ matrix.

Effect of LED and QD-LED(Quantum Dot) Treatments on Production and Quality of Red Radish(Raphanus sativus L.) Sprout (LED와 QD-LED(Quantum Dot) 광처리가 적무 새싹의 생산과 품질에 미치는 영향)

  • Choi, In-Lee;Wang, Lixia;Lee, Ju Hwan;Han, Su Jung;Ko, Young-Wook;Kim, Yongduk;Kang, Ho-Min
    • Journal of Bio-Environment Control
    • /
    • v.28 no.3
    • /
    • pp.265-272
    • /
    • 2019
  • The purpose of this study was to investigate the effects of LED and QD-LED (Quantum Dot) irradiation on seed germination, antioxidant ability, and microbial growth, during red radish (Raphanus sativus L.) sprouts cultivation. Irradiated light was blue, red, blue + red and blue + red + far red (QD-LED) lights, and the controls were a fluorescent lamp (FL), and dark condition. Germination rate of red radish was highest in the dark condition. The plant height and fresh weight of red radish sprouts that irradiated each light for 24 hrs after 7 days growing in dark condition, did not shown significantly difference among treatments. After 24 hrs of light irradiation, cotyledon green was best in blue + red light, and the red hypocotyl was excellent in blue light and QD-LED light. DPPH and phenol contents were high in dark and blue + red light treatment, and anthocyanin content was high in blue light and QD-LED light. Total aerobic counts were similar in all treatments and did not show bactericidal effect, whereas E. coli count was lowest in QD-LED light treatment, and yeast and mold counts were lowest in FL only treatment. Results suggest that when red radish seeds were germinated in dark condition and cultivated for 7 days as sprouts, and then treated with blue light or QD-LED light for 24 hrs, the seeds produced good quality red radish sprouts with greenish cotyledon, reddish hypocotyl, high anthocyanin content, and lower level of E coli contamination.

Characteristics of Graphene Quantum Dot-Based Oxide Substrate for InGaN/GaN Micro-LED Structure (InGaN/GaN Micro-LED구조를 위한 그래핀 양자점 기반의 산화막 기판 특성)

  • Hwang, Sung Won
    • Journal of the Semiconductor & Display Technology
    • /
    • v.20 no.3
    • /
    • pp.167-171
    • /
    • 2021
  • The core-shell InGaN/GaN Multi Quantum Well-Nanowires (MQW-NWs) that were selectively grown on oxide templates with perfectly circular hole patterns were highly crystalline and were shaped as high-aspect-ratio pyramids with semi-polar facets, indicating hexagonal symmetry. The formation of the InGaN active layer was characterized at its various locations for two types of the substrates, one containing defect-free MQW-NWs with GQDs and the other containing MQW-NWs with defects by using HRTEM. The TEM of the defect-free NW showed a typical diode behavior, much larger than that of the NW with defects, resulting in stronger EL from the former device, which holds promise for the realization of high-performance nonpolar core-shell InGaN/GaN MQW-NW substrates. These results suggest that well-defined nonpolar InGaN/GaN MQW-NWs can be utilized for the realization of high-performance LEDs.

Eco-Friendly Emissive ZnO-Graphene QD for Bluish-White Light-Emitting Diodes

  • Kim, Hong Hee;Son, Dong Ick;Hwang, Do-Kyeong;Choi, Won Kook
    • Proceedings of the Korean Vacuum Society Conference
    • /
    • 2013.02a
    • /
    • pp.627-627
    • /
    • 2013
  • Recently, most studies concerning inorganic CdSe/ZnS quantum dot (QD)-polymer hybrid LEDs have been concentrated on the structure with multiple layers [1,2]. The QD LEDs used almost CdSe materials for color reproduction such as blue, green and red from the light source until current. However, since Cd is one of six substances banned by the Restriction on Hazardous Substances (RoHS) directive and classified into a hazardous substance for utilization and commercialization as well as for use in life, it was reported that the use of CdSe is not suitable to fabricate a photoelectronic device. In this work, we demonstrate a novel, simple and facile technique for the synthesis of ZnO-graphene quasi-core.shell quantum dots utilizing graphene nanodot in order to overcome Cd material including RoHS materials. Also, We investigate the optical and structural properties of the quantum dots using a number of techniques. In result, At the applied bias 10 V, the device produced bluish-white color of the maximum brightness 1118 cd/$m^2$ with CIE coordinates (0.31, 0.26) at the bias 10 V.

  • PDF

Hybrid polymer-quantum dot based single active layer structured multi-functional device (Organic Bistable Device, LED and Photovoltaic Cell)

  • Son, Dong-Ick;Kwon, Byoung-Wook;Park, Dong-Hee;Kim, Tae-Whan;Choi, Won-Kook
    • Proceedings of the Korean Vacuum Society Conference
    • /
    • 2010.02a
    • /
    • pp.97-97
    • /
    • 2010
  • We demonstrate the hybrid polymer-quantum dot based multi-functional device (Organic bistable devices, Light-emitting diode, and Photovoltaic cell) with a single active-layer structure consisting of CdSe/ZnS semiconductor quantum-dots (QDs) dispersed in a poly N-vinylcarbazole (PVK) and 1,3,5-tirs- (N-phenylbenzimidazol-2-yl) benzene (TPBi) fabricated on indium-tin-oxide (ITO)/glass substrate by using a simple spin coating technique. The multi-functionality of the device as Organic bistable device (OBD), Light Emitting Diode (LED), and Photovoltaic cell can be successfully achieved by adding an electron transport layer (ETL) TPBi to OBD for attaining the functions of LED and Photovoltaic cell in which the lowest unoccupied molecular orbital (LUMO) level of TPBi is positioned at the energy level between the conduction band of CdSe/ZnS and LiF/Al electrode (band-gap engineering). Through transmission electron microscopy (TEM) study, the active layer of the device has a p-i-n structure of a consolidated core-shell structure in which semiconductor QDs are uniformly and isotropically adsorbed on the surface of a p-type polymer core and the n-type small molecular organic materials surround the semiconductor QDs.

  • PDF

Optical Simulation Study of the Improvement of Color-rendering Characteristics of White Light-emitting Diodes by Using Red Quantum-dot Films (적색 양자점 필름을 이용한 백색 발광 다이오드의 연색성 개선에 대한 광학 시뮬레이션 연구)

  • Lee, Gi Jung;Hong, Seung Chan;Lee, Jung-Gyun;Ko, Jae-Hyeon
    • Korean Journal of Optics and Photonics
    • /
    • v.32 no.4
    • /
    • pp.163-171
    • /
    • 2021
  • Conventional white light-emitting diodes (LEDs) for lighting applications consist of blue LEDs and yellow phosphors, the spectrum of which lacks deep red. To improve the color-rendering characteristics of white LEDs, a red quantum-dot film was applied to the diffuser plate of LED lighting. The mean free paths of the quantum dots and the concentration of the TiO2 particles in the diffuser plate were adjusted to optimize the optical structure of the lighting. The color-rendering index (CRI) was greater than 90 for most conditions, which demonstrates that adoption of the red quantum-dot film is an effective way for improving the color-rendering properties of conventional white LEDs. The angular dispersion of color coordinates could be removed by utilizing the optical cavity formed between the diffuser plate and the reflector on the bottom of the lighting, where multiple passages of the light through the quantum-dot film reduced the differences in optical path length depending on the viewing angle.