氮化碳薄膜的制备及研究现状

 氮化碳具有良好的物理、化学性质和广泛的应用前景。目前主要采用化学气相沉积法、离子束溅射法、激光等离子体沉积和激光烧蚀、离子镀、离子注入法等制备方法。文中对氮化碳的结构、性质、制备、性能表征以及研究现状进行了比较详细的介绍。     

120keV的N+注入SiC薄膜的光谱特性研究

文中主要研究了120keV的N⁺注入后SiC薄膜样品的光致发光谱(PL)和傅立叶红外光谱(FTIR)特性.从红外光谱可以看到有明显得碳氮单键、双键、三键等新结构生成.从PL光谱则发现365nm处的发光峰明显增强,这表明N⁺注入使得带隙中深的能级辐射中心复合的效率大幅度提高     

Modification of Fe/Cu multilayers under 400 keV Xe20+ irradiation

Two kinds of Fe/Cu multilayers with different modulation wavelength were deposited on cleaved Si(100) substrates and then irradiated at room temperature using 400 keV Xe²⁰⁺ in a wide range of irradiation fluences. As a comparison, thermal annealing at 300—900℃ was also carried out in vacuum. Then the samples were analyzed by XRD and the evolution of crystallite structures induced by irradiation was investigated. The obtained XRD patterns showed that, with increase of the irradiation fluence, the peaks of Fe became weaker, the peaks related to Cu-based fcc solid solution and Fe-based bcc solid solution phase became visible and the former became strong gradually. This implied that the intermixing at the Fe/Cu interface induced by ion irradiation resulted in the formation of the new phases which could not be achieved by thermal annealing. The possible intermixing mechanism of Fe/Cu multilayers induced by energetic ion irradiation was briefly discussed.     

注入Ar+的蓝宝石晶体退火前后光致发光谱的分析

对注入Ar⁺后不同晶面取向的蓝宝石晶体在不同退火条件下的光致发光谱进行了分析.分析结果表明:三种晶面取向的蓝宝石样品经Ar⁺注入后,其光致发光谱中均出现了新的位于506nm处的发光峰;真空和空气气氛下的退火均对样品在506nm处的发光有增强作用,不同晶面取向的样品发光增强程度不同,且发光增强至最大时的退火温度也不同,空气气氛下的退火使样品发光增强程度更为显著.由此可以看出,退火气氛、退火温度和晶面取向均对样品发光峰强度有影响. 关键词： 2O₃')" href="#">Al₂O₃ 离子注入 退火 光致发光谱     

快重离子辐照聚酰亚胺潜径迹的电子能损效应

快重离子辐照聚合物材料时，由于密集电离激发在其路径上产生几纳米直径的潜径迹，径迹形貌受离子种类、离子能量等多种因素的影响.为了研究电子能损对径迹形成所起的作用，利用1.158GeV 的Fe⁵⁶离子和 1.755GeV Xe¹³⁶离子在室温真空环境下辐照叠层聚酰亚胺(PI)薄膜，结合傅里叶转换红外光谱(FTIR)分析技术对辐照引起的化学变化进行了测量.聚酰亚胺官能团的降解及炔基的生成是离子辐照聚合物的主要特征，在注量1×10¹¹到6×10¹²/cm²范围及较宽的电子能损(dE/dX)_e范围 (Fe⁵⁶ 离子：2.2 到 5.2 keV/nm， Xe¹³⁶ 离子：8.6 到 11.3 keV/nm)对官能团的断键率及炔基生成率进行了研究. 红外结果显示在实验涉及的能损范围都有炔基生成，应用径迹饱和模型对实验结果进行拟合，不同能损下的平均损伤径迹半径及炔基生成径迹半径被得到，通过热峰模型对实验结果拟合，给出了离子在聚酰亚胺中产生潜径迹的能损阈值，实验给出的径迹形貌的电子能损效应曲线与热峰模型预言走势基本一致. 关键词： 离子辐照 潜径迹 红外光谱 热峰模型     

16Cr-ODS铁素体钢的初始氧化物弥散相结构对抗辐照硬化和Ne离子脆化性能的作用研究

依托兰州重离子研究装置(HIRFL),开展了3种不同氧化物弥散强化的16Cr-ODS铁素体钢的重离子辐照损伤研究,旨在探究氧化物颗粒结构参数(尺寸和密度)对材料辐照硬化和Ne离子辐照脆化效应的影响.采用6.17 MeV/u的Ni离子辐照和Ne离子,借助辐照终端的梯度减能装置在材料样品中产生了均匀的辐照损伤坪区.借助纳米...     

高能离子梯度多剂量辐照4H-SiC的微结构及硬度变化研究

为探讨高温高能离子辐照碳化硅后的结构和力学性能随剂量的变化,应用拉曼光谱和纳米压痕技术研究了122 MeV的²⁰Ne⁴⁺离子梯度多剂量辐照后的4H-SiC。研究表明,SiC的相对拉曼强度随剂量的增大呈指数规律下降,并出现了代表无序化Si-C键和同核Si-Si键的散射峰。基于DI/DS模型的初步拟合表明,在低剂量范围内扩展缺陷簇是引起SiC无序化的主要因素,高剂量范围内的无序化则是由离子直接碰撞过程的非晶化和扩展缺陷簇共同引起。辐照后的SiC硬度取决于位错钉扎和共价键断裂的共同作用,在0～4.00 dpa之间硬度随剂量增大而增大,在4.00～8.05 dpa之间硬度随剂量增大而减小,剂量在8.05 dpa时,硬度相比于未辐照区域略高,此时共价键断裂和位错钉扎达到平衡。     

高能238U离子辐照AlN 晶体薄膜的光学特性研究

通过傅里叶变换红外光谱、拉曼光谱和光致发光谱测试手段分析了由HIRFL 提供的高能238U离子辐照AlN 晶体薄膜的光学特性变化。辐照后出现了A1(To),A1(Lo),E1(To) 和E2 等声子振动吸收模式,并且辐照使其在样品近表面Al—N 等振动模式遭到破坏后悬空的Al— 键很快与空气中的O离子发生结合,形成了Al—O 键。综合分析得出了蓝光发射带是与O 离子相关的VAl-ON-3N 和VAl-2ON-2N两种类型缺陷以及F-型缺陷聚合所致;绿光发射带是由基底中Al 原子产生的价带之间的跃迁所致。AlN thin film irradiated with 100 MeV 238U ions delivered from HIRFL (Heavy Ion Research Facility in Lanzhou) were investigated by Fourier Transform Infrared spectra, Raman spectra and Photoluminescence spectra. Phonon vibration absorption modes including A1(To), A1(Lo), E1(To) and E2 appeared in the irradiated samples. The irradiation made the Al—N bonds broken and the formation of Al—dangling bonds, which combined soon with oxygen atoms existing in air to form Al—O bonds. Blue light emission band are related to the two types of defects of VAl-ON-3N and VAl-2ON-2N and F-type defects aggregation. Green light emission band is due to energy transition among valence band of Al atoms in sapphire substrate.     

退火对He注入及随后208 Pb27+辐照的Al2O3单晶PL谱的影响

利用高能离子研究了110 keV的He+注入Al2O3单晶及随后230 MeV的208pb27+辐照并在不同温度条件下退火样品的光致发光的特性.从测试结果可以清楚地看到在375 nm,390 nm,413 nm和450 nm出现了强烈的发光峰.经过600 K退火2 h后测试结果显示,390 nm发光峰增强剧烈,而别的发光峰显示不明显.在900 K退火条件下,390 nm的发光峰开始减弱相反在510 nm出现了较强的发光峰,到1100 K退火完毕后390 nm的发光峰完全消失,而510 nm的发光峰相对增强.从辐照样品的FTIR谱中看到,波数在460-510 cm-1间的吸收是振动模式,经过离子辐照后,吸收带展宽,随着辐照量的增大,Al2O3振动吸收峰消失,说明Al2O3振动模式被完全破坏.1000-1300cm-1之间为Al-O-Al桥氧的伸缩振动模式,辐照后吸收带向高波数方向移动.退火后的FTIR谱变化不大.     

离子注入/辐照引起Al2O3单晶的改性研究

600K温度下用110keV的He^＋,Ne^＋,Ar^＋离子注入及320K温度下用230MeV的^208Pb^27＋辐照Al2O3单晶样品,研究了离子注入和辐照对Al2O3单晶样品结构和光学特性的影响。从测得的光致发光谱可以清楚地看到,所有样品在波长为375,413和450nm处出现了强的发光峰。且所有5×10^16ion／cm^2注入样品的发光峰均最强。经过高能Pb辐照后的样品,在390nm处出现了新的发光峰。透射电镜分析发现在注入氖样品100nm入射深度以内形成了高浓度的小空洞（1-2nm）,在Ne沉积区域有少量大空洞形成。傅立叶变换红外光谱分析发现,波数在460-510cm^-1间的振动吸收带经过离子辐照后展宽,随着辐照量的增大,该振动吸收强度显著减弱。1000—1300cm^-1对应Al-O-Al桥氧伸缩振动模式的吸收带,辐照后向高波数方向移动。对离子注入和辐照对Al2O3单晶样品结构损伤机理进行了初步探讨。Single crystal sapphire （Al2O3 ） samples were implanted at 600 K by He, Ne and Ar ions with energy of 110 keV to doses ranging from 5 × 10^16 to 2× 10^17 ion/cm^2 or irradiated at 320 K by ^208Pb^27＋ ion with energy of 1.1 MeV/u to the fluences ranging from 1 × 10^12 to 5 × 10^14 ion/cm^2. The modification of structure and optical properties induced by ion implantation or irradiation were analyzed by using photoluminescence（PL） and Fourier transformation infrared spectrum（FIR） spectra and transmission electron microscopy（ TEM ） measurements. The PL measurements showed that absorption peaks located at 375,413 and 450 nm appeared in all the implanted or irradiated samples, the PL intensities reached up to the maximum for the 5 × 10^16 ion/cm^2 implanted samples. After Pb-ion irradiation, a new peak located at 390 nm formed. TEM analyses showed that small size voids,（ 1--2 nm） with high density were formed in the region from the surface till to about 100 nm in depth and also large size Nebubble formed in the Ne-doped region. From the obtained FTIR spectra, it was found that Pb-ion irradiation induced broadening of the absorption band in 460-510 cm^-1 and position shift of the absorption band in 1 000- 1 300 cm^- 1 towards to high wavenumber. The possible damage mechanism in single crystal sapphire induced by energetic ion implantation or irradiation was briefly discussed.