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Study Of The New Fast And High-sensitivity CQDs IR Photodetector

Posted on:2014-07-10Degree:MasterType:Thesis
Country:ChinaCandidate:J Q SongFull Text:PDF
GTID:2268330422963391Subject:Microelectronics and Solid State Electronics
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In recent years, the infrared photodetector, based on colloidal quantum dots(CQDs), hasbecome the hotspot of nano-science and technology, owing to its outstanding photoelectricperformance. And this new CQDs IR photodetector gets the fast response speed and highsensitivity. Meanwhile, its wide range applications involve communication、safety、organism、illumination and other fields, owning an immense market value in the future.The development of IR detector has been running for a long history, and currently itsmain classifications include HgCdTe detector, QWIP and QDIP. Because of tunablespectrum and simple process, CQDs push IR detector to advance further and deeper.We chose the solution process to synthesize PbS nanocrystals, and the process using insitu generated H2S as the sulfur source is very innovative.In the preparation of PbS CQDs detector, firstly we carried out the ligand-exchange foras-synthesized PbS nanocrystals(butylamine replacing oleic acid), then prepare the Agelectrode on glass substrate by photoetching, and at last spin-casted PbS film on electrode.We also showed the characterization of PbS CQDs and as-synthesized IR detector,including XRD, TEM, FTIR and I-V performance.The as-synthesized PbS CQDs got excellent monodispersity and high purity, andshowed various structures and sizes under different growing conditions. For the detectormade by them, the photocurrent under illumination was much bigger than the dark current,demonstrating the good sensitivity. The ligand-exchange by butylamine was successful, andan obvious improvement was obtained on the electrical transmission for ligand-exchangedPbS nanocrystals. As a result, for the PbS CQDs detector after ligand-exchange, the linearityof its I-V performance was straighter, and its responsibility reached the order of A/W.
Keywords/Search Tags:colloidal quantum dots(CQDs), solution process, Lead Sulfide, ligandsexchange, photoelectric performance
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