• Title/Summary/Keyword: ZnO 양자점

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CdSe Quantum Dot based Transparent Light-emitting Device using Silver Nanowire/Ga-doped ZnO Composite Electrode (AgNWs/Ga-doped ZnO 복합전극 적용 CdSe양자점 기반 투명발광소자)

  • Park, Jehong;Kim, Hyojun;Kang, Hyeonwoo;Kim, Jongsu;Jeong, Yongseok
    • Journal of the Semiconductor & Display Technology
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    • v.19 no.4
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    • pp.6-10
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    • 2020
  • The silver nanowires (AgNWs) were synthesized by the conventional polyol process, which revealed 25 ㎛ and 30 nm of average length and diameter, respectively. The synthesized AgNWs were applied to the CdSe/CdZnS quantum dot (QD) based transparent light-emitting device (LED). The device using a randomly networked AgNWs electrode had some problems such as the high threshold voltage (for operating the device) due to the random pores from the networked AgNWs. As a method of improvement, a composite electrode was formed by overlaying the ZnO:Ga on the AgNWs network. The device used the composite electrode revealed a low threshold voltage (4.4 Vth) and high current density compared to the AgNWs only electrode device. The brightness and current density of the device using composite electrode were 55.57 cd/㎡ and 41.54 mA/㎠ at the operating voltage of 12.8 V, respectively, while the brightness and current density of the device using (single) AgNWs only were 1.71 cd/㎡ and 2.05 mA/㎠ at the same operating voltage. The transmittance of the device revealed 65 % in a range of visible light. Besides the reliability of the devices was confirmed that the device using the composite electrode revealed 2 times longer lifetime than that of the AgNWs only electrode device.

Shortwave Infrared Photodetector based on PbS Quantum Dots for Eye-Safety Lidar Sensors (Eye safety 라이다 센서용 황화납 양자점 기반 SWIR photodetector 개발)

  • Suji Choi;JinBeom Kwon;Yuntae Ha;Daewoong Jung
    • Journal of Sensor Science and Technology
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    • v.32 no.5
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    • pp.285-289
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    • 2023
  • Recently, the demand for lidar systems for autonomous driving is increasing, and research on Shortwave Infrared(SWIR) photodetectors for this purpose is being actively conducted. Most SWIR photodetectors currently being developed are based on InGaAs, and have the disadvantages of complex processes, high prices, and limitations in research due to monopoly. In addition, current SWIR photodetectors use lasers in the 905 nm wavelength band, which can pass through the pupil and cause damage to the retina. Therefore, it is required to develop a SWIR photodetector using a wavelength band of 1400 nm or more to be safe for human eyes, and to develop a material that can replace the proprietary InGaAs. PbS QDs are group 4-6 compound semiconductors whose absorption wavelength band can be adjusted from 1000 to 2700 nm, and have the advantage of being simple to process. Therefore, in this study, PbS QDs having an absorption wavelength peak of 1415 nm were synthesized, and a SWIR photodetector was fabricated using this. In addition, the photodetector's responsivity was improved by applying P3HT and ZnO NPs to improve electron hole mobility. As a result of the experiment, it was confirmed that the synthesized PbS QDs had excellent FWHM characteristics compared to commercial PbS QDs, and it was confirmed that the photodetector had a maximum current change of about 1.6 times.