共查询到19条相似文献,搜索用时 78 毫秒
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碘化铅单晶生长及探测器的研究进展 总被引:1,自引:1,他引:0
PbI2单晶体是性能优异的室温半导体核辐射探测器新材料。主要介绍了PbI2晶体生长技术及其室温核辐射探测器研究发展的最新动态,综述了PbI2晶体的3种主要生长方法(气相法、熔体法和凝胶法)的原理和优缺点,重点阐述了熔体法生长PbI2晶体的影响因素及研究进展,提出了PbI2单晶制备技术存在的主要问题和今后的发展方向。 相似文献
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研究了一种新型近红外光电探测材料碲铟汞(MIT)晶体,利用垂直Bridgman法成功生长了MIT单晶,并采用X-ray衍射分析、UV-NIR-IR光谱分析及Hall测试对晶体的形态结构及光电性能进行了检测。结果表明:MIT晶体为缺陷闪锌矿结构,其在中远红外波段透过性能较好( 〉50%),并且随着波长的增大,透过增强.MIT晶体为n型半导体,室温电阻率为4.79×10^2Ω.cm,载流子迁移率为4.6×10^2cm^2.V^-1.s^-1,载流子浓度为2.83×10^13cm^-3。较低的载流子浓度,有利于降低探测器的噪声及提高探测器的能量分辨率。 相似文献
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通过高温高压方法,成功地合成出了立方相(PbTe1.04)100-y(PbI2)y(0≤y≤ 0.065)体热电材料.在常温常压下,对样品的一系列电学性质进行了测试与研究.结果表明,随着掺杂量的增加,Seebeck系数的绝对值和电阻率均显著地减小.当y=0.015时,热电材料的功率因子达到最大值24.2μW/(cm·K2),它远远大于常压下合成PbTe掺杂PbI2的功率因子.以上结果说明,高温高压结合微量掺杂的方法可以有效地提高PbTe材料的电学输运性能. 相似文献
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采用垂直布里奇曼法成功制备出尺寸为Φ25 mm×70 mm的SrI2∶Eu∶Cs晶体,经加工后封装得到尺寸为10 mm×10 mm×10 mm的透明单晶,这是迄今为止Eu2+和Cs+双掺杂的最大尺寸SrI2单晶,所用原料为国产原料。XRD测试结果表明,所得晶体为SrI2正交相,空间群为Pbca。荧光光谱显示晶体的发射峰和激发峰分别位于440 nm和419 nm,属于典型Eu2+的5d→4f跃迁发射。X射线激发发射光谱显示该晶体只有一个位于440 nm的发射峰,与荧光光谱的结果一致。采用单指数拟合后得到晶体在370 nm激发波长下的荧光寿命约为1.3 μs。在137Cs射线源激发下的γ能谱测试显示晶体的能量分辨率为5.5%,已基本满足实际使用的要求。 相似文献
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采用单温区法合成了CdSiP2 (CSP)多晶原料, 然后采用垂直布里奇曼法生长了大尺寸的CSP单晶。采用扫描电子显微镜、EDS对晶体中光散射颗粒的尺寸、形貌和成分进行了观察和检测。测试结果表明, 所生长的CSP晶体中的光散射颗粒呈近椭圆形, 尺寸为2~8 μm, 主要成分为Si, 含量占88%以上。对CSP多晶合成的反应机理研究表明, 此第二相颗粒是由于合成时多晶料中残留有少量未反应的Si单质所致。通过合成工艺的改进, 有效地减少了晶体中Si散射颗粒的残留, 制备出了高透明性的CSP单晶体。 相似文献
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基于绝缘体上硅(SOI)的CMOS电路具有天然的抗单粒子优势,但绝缘埋层的存在使得其总剂量效应尤为突出和复杂。本文研究了利用离子注入改性SOI材料的总剂量辐射和退火效应、基于赝MOS技术的SOI材料辐射效应评估技术和离子注入改性提高SOI材料抗辐射性能的机理。实验结果表明,采用该技术制备的绝缘体上硅材料抗总剂量能力达到1Mrad(Si);离子注入改性SOI材料在经过室温和高温退火后,辐射导致的固定电荷和界面态可以完全恢复;离子注入和高温退火在二氧化硅薄膜中形成硅纳米团簇结构,从而引入深电子陷阱,补偿总剂量辐射引起的绝缘埋层中的空穴积累。 相似文献
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The In‐Gap Electronic State Spectrum of Methylammonium Lead Iodide Single‐Crystal Perovskites 下载免费PDF全文
Valerio Adinolfi Mingjian Yuan Riccardo Comin Emmanuel S. Thibau Dong Shi Makhsud I. Saidaminov Damir Kopilovic Sjoerd Hoogland Zheng‐Hong Lu Osman M. Bakr Edward H. Sargent 《Advanced materials (Deerfield Beach, Fla.)》2016,28(17):3406-3410
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Ⅳ-ⅥSnS e单晶是一种引人注目的热电材料,不仅热电性能优异而且还具有环境友好的特征。本工作探索了一种制备SnS e单晶的技术,并对产品的力学性能进行研究。利用坩埚下降法成功生长了化学计量比准确的非掺杂SnS e单晶,其在室温下具有标准Pnma正交相结构。由于Sn层与Se层之间的结合力非常弱, SnSe单晶很容易沿(100)面解理。显微压痕测试表明SnSe单晶十分柔软, 0.01~0.05 kg载荷下的平均显微维氏硬度HV仅为53 MPa。然而,得益于层内Sn和Se原子之间强烈的极性耦合, SnSe单晶沿(100)面却展现出了优异的断裂韧性。纳米划痕实验显示SnS e单晶(100)面在5~300 mN划痕压力范围内的摩擦系数COF可从0.09增加到0.8。本工作对完善SnS e单晶的力学性能信息具有重要意义。 相似文献
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Cheng Li Antonio Guerrero Yu Zhong Anna Gräser Carlos Andres Melo Luna Jürgen Köhler Juan Bisquert Richard Hildner Sven Huettner 《Small (Weinheim an der Bergstrasse, Germany)》2017,13(42)
Organic–inorganic metal halide perovskites (e.g., CH3NH3PbI3?x Clx ) emerge as a promising optoelectronic material. However, the Shockley–Queisser limit for the power conversion efficiency (PCE) of perovskite‐based photovoltaic devices is still not reached. Nonradiative recombination pathways may play a significant role and appear as photoluminescence (PL) inactive (or dark) areas on perovskite films. Although these observations are related to the presence of ions/defects, the underlying fundamental physics and detailed microscopic processes, concerning trap/defect status, ion migration, etc., still remain poorly understood. Here correlated wide‐field PL microscopy and impedance spectroscopy are utilized on perovskite films to in situ investigate both the spatial and the temporal evolution of these PL inactive areas under external electric fields. The formation of PL inactive domains is attributed to the migration and accumulation of iodide ions under external fields. Hence, we are able to characterize the kinetic processes and determine the drift velocities of these ions. In addition, it is shown that I2 vapor directly affects the PL quenching of a perovskite film, which provides evidence that the migration/segregation of iodide ions plays an important role in the PL quenching and consequently limits the PCE of organometal halide‐based perovskite photovoltaic devices. 相似文献
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Yan Sun Zishu Zhou Zhen Huang Jiangbin Wu Liujiang Zhou Yang Cheng Jinqiu Liu Chao Zhu Maotao Yu Peng Yu Wei Zhu Yue Liu Jian Zhou Bowen Liu Hongguang Xie Yi Cao Hai Li Xinran Wang Kaihui Liu Xiaoyong Wang Jianpu Wang Lin Wang Wei Huang 《Advanced materials (Deerfield Beach, Fla.)》2019,31(17)
To explore new constituents in two‐dimensional (2D) materials and to combine their best in van der Waals heterostructures is in great demand as being a unique platform to discover new physical phenomena and to design novel functionalities in interface‐based devices. Herein, PbI2 crystals as thin as a few layers are synthesized, particularly through a facile low‐temperature solution approach with crystals of large size, regular shape, different thicknesses, and high yields. As a prototypical demonstration of band engineering of PbI2‐based interfacial semiconductors, PbI2 crystals are assembled with several transition metal dichalcogenide monolayers. The photoluminescence of MoS2 is enhanced in MoS2/PbI2 stacks, while a dramatic photoluminescence quenching of WS2 and WSe2 is revealed in WS2/PbI2 and WSe2/PbI2 stacks. This is attributed to the effective heterojunction formation between PbI2 and these monolayers; type I band alignment in MoS2/PbI2 stacks, where fast‐transferred charge carriers accumulate in MoS2 with high emission efficiency, results in photoluminescence enhancement, and type II in WS2/PbI2 and WSe2/PbI2 stacks, with separated electrons and holes suitable for light harvesting, results in photoluminescence quenching. The results demonstrate that MoS2, WS2, and WSe2 monolayers with similar electronic structures show completely distinct light–matter interactions when interfacing with PbI2, providing unprecedented capabilities to engineer the device performance of 2D heterostructures. 相似文献
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Manukumara Manjappa Ankur Solanki Abhishek Kumar Tze Chien Sum Ranjan Singh 《Advanced materials (Deerfield Beach, Fla.)》2019,31(32)
Solution‐processed lead iodide (PbI2) governs the charge transport characteristics in the hybrid metal halide perovskites. Besides being a precursor in enhancing the performance of perovskite solar cells, PbI2 alone offers remarkable optical and ultrasensitive photoresponsive properties that remain largely unexplored. Here, the photophysics and the ultrafast carrier dynamics of the solution processed PbI2 thin film is probed experimentally. A PbI2 integrated metamaterial photonic device with switchable picosecond time response at extremely low photoexcitation fluences is demonstrated. Further, findings show strongly confined terahertz field induced tailoring of sensitivity and switching time of the metamaterial resonances for different thicknesses of PbI2 thin film. The approach has two far reaching consequences: the first lead‐iodide‐based ultrafast photonic device and resonantly confined electromagnetic field tailored transient nonequilibrium dynamics of PbI2 which could also be applied to a broad range of semiconductors for designing on‐chip, ultrafast, all‐optical switchable photonic devices. 相似文献
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本文报道了Pb2MoO5单晶的坩埚下降法生长工艺.按照精确的化学计量比进行配料,应用高温固相反应合成Pb2MoO5多晶料;在晶体生长过程中,控制炉体温度于1050~1070℃,调节固液界面温度梯度为30~40℃/cm,按照0.6~1.0 mm/h的下降速率,通过改进的坩埚下降法生长出透明完整的Pb2MoO5单晶;应用X射线衍射、差热分析、透射光谱等方法进行了单晶基本性质的表征.X射线衍射分析证实该晶体为单斜晶系,DTA/TG曲线表明该晶体在958℃一致熔融,高于此温度熔体组分出现严重挥发,该晶体在可见光波长范围具有良好的光学透过性,其吸收边位于370 nm波长附近. 相似文献