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氮是金刚石中最常见的杂质之一, 其对金刚石的缺陷发光具有重要的影响. 氮可以与金刚石中的本征缺陷形成复合缺陷. 本文首先利用阴极射线发光照片(CL)对一个高温高压合成的氮掺杂金刚石进行表征, 发现{100}晶面为蓝色, 然后利用透射电子显微镜(TEM)对该晶面进行电子辐照及后续退火处理, 以引入本征点缺陷进而形成含氮的复合缺陷, 并利用低温光致发光光谱(PL光谱)表征其缺陷发光特性, 发现该晶面主要以氮-空位复合缺陷(NV中心)发光为主, 并伴随着较弱的503 nm发光.
关键词:
金刚石
缺陷
发光 相似文献
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硅的中子嬗变掺杂(NTD)已经得到了广泛应用,在制备大功率整流器、可控硅、硅靶摄像管、核探测器和集成电路等方面巳被公认是一个好的方法[1-3].NTD硅的优点是掺杂十分均匀,浓度偏差可在±5%之内,而且它的掺杂精度很高,能够准确地达到所要求的浓度. 1971年苏联的 Sh.M.Mirishvili等人[4]报道了GaAs的中子嬗变掺杂,在这以后,一些作者进一步研究了热中子辐照GaAs的原理、光致发光性质及其应用[5-8]. 用常规掺杂方法在砷化棕中引入施主杂质时,总是伴随着受主浓度的增加.在掺杂浓度较低时,n型GaAs具有明显的补偿,。。/。。一般超过0.3,而在… 相似文献
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退火对ZnS纳米晶结构相变及发光的影响 总被引:4,自引:0,他引:4
采用共沉淀法制备了ZnS及ZnS:Eu纳米晶粉末,并对其在不同温度进行了退火处理。通过X射线粉末衍射(XRD)技术及差热分析实验(DTA)对ZnS纳米粒子在退火过程中的从立方到六角晶相的结构相变进行了研究。实验结果表明,同体材料相比,由于ZnS纳米晶具有较大的表面活性,其相变温度大大降低了。在由纳米粉末退火制备的样品中,观察到峰值位于460nm和520nm的两个发光带。前者是ZnS的自激活发光;后者归因于纳米晶制备过程中引入的缺陷或者在退火过程中形成了杂质能级。在退火温度低于800℃条件下,由纳米粒子制备的样品和由商用生粉制备的荧光粉相比较,前者的发光明显较强。铕的掺杂并没有形成新的发光中心,但却极大的增强了ZnS的缺陷发光。 相似文献
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在纳米晶体硅制备的过程中, 晶化处理是影响和提高纳米硅发光效率的重要制备环节. 热退火、激光退火和电子束辐照是使纳米硅样品晶化的不同方式. 实验表明: 选取适当的晶化方式和参量对制备纳米硅晶体结构至关重要, 特别是在制备硅量子点和量子面的过程中控制好参量, 可以得到较高的发光效率. 有趣的是, 在实验中发现: 当晶化时间较短(如低于20 min)时, 可以获得较好的纳晶硅结构(如量子点结构), 对应于较好的纳晶硅光致发光(PL)和掺杂局域态发光; 当晶化时间较长(如超过30 min)时, 纳米晶体硅结构被破坏, 致使PL谱逐渐减弱与消失. 结合热退火、激光退火和电子束辐照对纳米硅晶化过程, 本文建立起晶化时间对纳米硅局域态发光影响机理的物理模型, 解释了晶化时间对纳米硅局域态发光的影响. 相似文献
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测量了α-Al2O3: Mn单晶中子辐照前后的三维热释发光谱.观察到α-Al2O3: Mn:Mn单晶γ射线照射后测量的三维热释发光谱中,峰温在350℃波长为680nm处有一宽发光峰,这可能与Mn2+离子有关;波长为695nm峰温在170℃和350℃的线状光谱,叠加在680nm宽发光峰上,是Cr3+离子的发光谱线,其中可能有Mn4+离子的贡献.与纯α-Al2O3单晶的热释发光谱相比,掺入Mn杂质后,γ射线照射的三维热释发光谱中完全地抑制了波长为416nm的α-Al2O3的F心发光峰.经1017cm-2中子注量辐照和退火后,γ射线照射后测量的三维热释发光谱中,在150℃出现了波长为416和695nm的发光峰,以及在250℃波长为680和695nm的发光峰,其中695nm新发光峰的强度略超过了中子辐照前α-Al2O3:Mn在350℃波长为695nm的发光峰,说明中子辐照产生了大量浅陷阱能级和F心.然而,经1018cm-2中子注量辐照和退火后,γ射线照射后测量的三维热释发光谱中,出现了峰温150℃,190℃和250℃波长为520nm的Mn2+离子发光峰,以及300℃波长为680和695nm的Cr3+(或Mn4+)的发光峰,表明增高中子注量的辐照,产生了温度为190℃,250℃和300℃深陷阱能级和F心,并使Mn2+离子发光峰明显加强.
关键词:
α-Al2O3:Mn
三维发光谱
缺陷结构
发光机理 相似文献
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卤化铅钙钛矿(LHPs)由于具有优异的光电性能和制备成本低等优点,已成为新一代光电器件的有力候选材料。然而,缺陷造成的离子迁移会导致LHPs纳米晶的晶体结构解离分解。因此,稳定性成为LHPs实际应用中亟待解决的问题。本文旨在研究镍离子替位掺杂及卤素空位填补对CsPbBr3纳米晶中的离子迁移抑制作用。通过离子迁移活化能的测定和高分辨透射电镜的原位观察,分析了前驱体掺杂剂对加强LHPs稳定性的作用原理。首先,选用乙酰丙酮镍和溴化镍作为掺杂剂,合成了掺杂LHPs纳米晶。其次,通过吸收-荧光光谱,X射线衍射,X射线光电子衍射,透射电子显微镜等测试手段对掺杂样品的光学及化学组成进行分析。最后,通过纳米晶薄膜电导率的温度依赖关系计算出其离子迁移活化能,并结合高分辨电镜原位观察纳米晶在高能电子束辐照下的形貌演变过程,揭示了不同掺杂剂对合成掺杂LHPs稳定性的影响。实验结果表明:Ni2+掺杂CsPbBr3样品的离子迁移活化能相较本征CsPbBr3样品(0.07 eV)有显著提升,其中乙酰丙酮镍掺杂样品的离子迁移活化能为0.238 eV,溴化镍掺杂样品的离子迁移活化能为0.487 eV。另外,电子束辐照测试表明溴化镍掺杂钙钛矿晶体表现出更高的结构稳定性,这主要归因于掺杂的Ni2+对卤素的强结合和卤素填补空位缺陷的协同钝化作用。Ni2+掺杂和卤素空位填充协同可以有效抑制卤化物钙钛矿纳米晶体中的离子迁移。 相似文献
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Youwen Hu Tiecheng Lu Shaobo Dun Qiang Hu Ningkang Huang Songbao Zhang Junlong Dai Issai Shlimak Qiangmin Wei 《Solid State Communications》2007,141(9):514-518
We have succeeded in doping arsenic (As) impurities into isotope germanium nanocrystals (nc-74Ge) uniformly dispersed in a SiO2 matrix by using the neutron transmutation doping (NTD) method. The samples’ inner structural transmutation is studied by combining Raman scattering, X-ray fluorescence (XRF), X-ray photoelectron spectroscopy (XPS) and Transmission electron microscope (TEM) methods. The Raman spectrum of the doped sample exhibits a relative intensity increase of the low frequency tail, blue shift of the main Raman peak (∼300 cm−1) and a high frequency tail, while the undoped sample does not. Together with the XRF, XPS and TEM, we believe that the relative intensity increase of the low frequency tail arises from an increase of amorphous 74Ge (a-74Ge) induced by the irradiation damage. The blue shift of the main Raman peak comes from the mismatch of the crystal lattice which arose from the As impurity introduction. And the high frequency tail is due to transmuted-impurities (As) in the nc-74Ge which was introduced by NTD. 相似文献
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Shaobo Dun Youwen Hu Liuqi Yu Ningkang Huang Bin Tang Lev Resnick 《Journal of luminescence》2008,128(8):1363-1368
Samples of nanocrystalline 74Ge embedded in amorphous SiO2 film were prepared by 74Ge ion implantation and subsequent primary thermal annealing. These samples were irradiated by neutron flux in a nuclear reactor then the second annealing followed. Irradiation with thermal neutrons leads to doping of nanocrystalline 74Ge with As impurities due to nuclear transmutation of isotope 74Ge into 75As. Transmission electron microscope, X-ray fluorescence, X-ray photoelectron spectroscopy, laser Raman scattering and photoluminescence of the obtained samples were measured. It was observed that with the increase in As-donors concentration, photoluminescence intensity first increased but then significantly decreased. An explanatory model of this non-monotonic behavior was discussed. 相似文献
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P. G. Baranov A. N. Ionov I. V. Il’in P. S. Kop’ev E. N. Mokhov V. A. Khramtsov 《Physics of the Solid State》2003,45(6):1030-1041
Potential applications of electron paramagnetic resonance (EPR) for investigating and controlling the process of neutron transmutation doping (NTD) of semiconducting germanium, silicon, and silicon carbide are discussed. It is shown that EPR enables one to control the process of annealing of radiation-induced defects in semiconductors subject to neutron irradiation and to detect the shallow donors restored in the process of annealing of donor-compensating defects by observing EPR signals from these donors. EPR can be used to separately detect isolated donors and clusters of two, three, and more exchange-bound donor atoms and thereby determine the degree of nonuniformity of the impurity distribution over the crystal. Neutron transmutation doping is demonstrated to produce a fairly uniform arsenic-donor distribution in a germanium crystal. It is argued that semiconductors enriched in the selected isotopes should be used for NTD. The results of an investigation of phosphorus donors in silicon carbide are presented. 相似文献
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I. S. Shlimak 《Physics of the Solid State》1999,41(5):716-719
Different aspects of neutron transmutation doping (NTD) of silicon and germanium are considered, with a special emphasis on
the contribution by scientists of the Ioffe Physicotechnical Institute, Russian Academy of Sciences, to the solution of these
problems. Fundamental studies related to determination of the cross sections of thermal-neutron capture by isotopes of semiconducting
materials, annealing of radiation defects produced by fast reactor neutrons, and the use of NTD for probing the structure
of the Ge impurity band are reviewed. Problems involved in industrial-scale production of NTD-Si, application of NTD-Si and
NTD-Ge to fabrication of power thyristors, nuclear-particle and IR detectors, deep-cooled thermistors, and bolometers are
discussed. The paper concludes with a consideration of prospects in the application of NTD-Si and NTD-Ge based on the use
of materials with a controlled isotopic composition.
Fiz. Tverd. Tela (St. Petersburg) 41, 794–798 (May 1999) 相似文献
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B. J. Heijmink Liesert M. Godlewski T. Gregorkiewicz C. A. J. Ammerlaan 《Applied Surface Science》1991,50(1-4):245-248
An unambiguous proof for successful neutron transmutation doping (NTD) of GaP is presented on the basis of optically detected magnetic resonance (ODMR). GaP:S samples grown by the liquid encapsulated Czochralski method were irradiated with thermal neutrons and subsequently annealed at 800°C. In the ODMR experiments the transmuted Ge substitutional on Ga sites was detected. The NTD process was also found to create deep acceptors, the nature of which will be tentatively discussed. 相似文献
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SiO2 layer structures with a middle layer containing Ge nanocrystals were prepared by sputtering on n- and p-type Si substrates, and by consecutive annealing. Ge content in the middle layer was varied in the range of 40-100%. Most of the structures exhibited low breakdown voltages. The current through the structures became Schottky-like after breakdown. However, some p-type samples showed a considerable memory effect. It was obtained by spectroscopic ellipsometry that the middle layer contains amorphous Ge phase as well. The results also suggest intermixing of the layers during the sputtering and/or the annealing process. 相似文献
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Nanocrystals of Ge surrounded by a germanium oxide matrix have been formed by dry thermal oxidation of polycrystalline SiGe layers. Violet (3.16 eV) luminescence emission is observed when Ge nanocrystals, formed by the oxidation of the Ge segregated during the oxidation of the SiGe layer, are present, and vanishes when all the Ge has been oxidized forming GeO2. Based on the evolution of the luminescence intensity and the structure of the oxidized layer with the oxidation time, the recombination of excitons inside the nanocrystals and the presence of defects in the bulk oxide matrix are ruled out as sources of the luminescence. The luminescence is attributed to recombination in defects at the Ge sub-oxide interface between the Ge nanocrystals and the surrounding oxide matrix, which is GeO2. 相似文献
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研究了高掺硅的n型GaAs在中子辐照前后和150℃-500℃等时热退火以后的光致发光光谱。观察到在中子辐照后积分发光强度降低为辐照前的1/36。在退火温度超过250℃时,积分发光强度显著增长,当退火温度达400℃以上时,在带边峰的低能侧出现能量为1.35eV、1.30eV和1.26eV的发光峰。假设250℃退火阶段对应于较大的空位团分解为较小的空位团,400℃退火阶段对应于较小的空位团分解出VGa,可以较好地解释实验现象。 相似文献
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N. Srinivasa Rao A.P. Pathak N. Sathish G. Devaraju V. Saikiran P.K. Kulriya D.C. Agarwal G. Sai Saravanan D.K. Avasthi 《Solid State Communications》2010,150(43-44):2122-2126
Ge nanocrystals embedded in an SiO2 matrix were prepared by the atom beam co-sputtering (ABS) method from a composite target of Ge and SiO2. The as-deposited films were rapid thermally annealed at the temperatures 700 and 800 °C in nitrogen ambience. The structure of the films was evaluated by using X-ray diffraction (XRD) and Raman spectroscopy. XRD results reveal that as-deposited films are amorphous in nature whereas annealed samples show crystalline nature. Raman scattering spectra showed a peak of Ge–Ge vibrational mode shifted downwards to 297 cm?1, presumably caused by quantum confinement of phonons in the Ge nanocrystals. Rutherford backscattering spectrometry has been used to measure the thickness and Ge composition of the composite films. Size variation of Ge nanocrystals with annealing temperature has been discussed. The advantages of ABS over other methods are highlighted. 相似文献
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Fei Gao Martin A. Green Eun-Chel Cho Ivan Perez-Wurfl 《Applied Surface Science》2008,254(22):7527-7530
Multilayered Ge nanocrystals embedded in SiOxGeNy films have been fabricated on Si substrate by a (Ge + SiO2)/SiOxGeNy superlattice approach, using a rf magnetron sputtering technique with a Ge + SiO2 composite target and subsequent thermal annealing in N2 ambient at 750 °C for 30 min. X-ray diffraction (XRD) measurement indicated the formation of Ge nanocrystals with an average size estimated to be 5.4 nm. Raman scattering spectra showed a peak of the Ge-Ge vibrational mode downward shifted to 299.4 cm−1, which was caused by quantum confinement of phonons in the Ge nanocrystals. Transmission electron microscopy (TEM) revealed that Ge nanocrystals were confined in (Ge + SiO2) layers. This superlattice approach significantly improved both the size uniformity of Ge nanocrystals and their uniformity of spacing on the ‘Z’ growth direction. 相似文献