极性纳米晶半导体的非晶特性(英文)

The crystallography property of typical polar nano- crystalline semiconductors (PNCSs), SIC nano-rods (NRs) ,GaN NANO- wires (NWs)and ZnO nano - particulars (NPs) ,has been investigated.The TEM and XRD measurements exhibited that the samples are crystalline and size- distributed with the average size of 4 - 12nm.     

重电子金属CeCu5.8 M0.2(M=Ni,Zn,Cd) 低温物性的比较

研究了不同元素等量掺杂下重电子金属CeCu5.8M0.2(M=Ni,Zn,Cd)低温电阻、比热容和磁化率随温度的变化关系.分析讨论了掺杂元素M(M=Ni,Zn,Cd)的磁性、价态及原子尺寸对近藤温度Tk、相干温度(即电阻极大值的温度TRmax)、每个Ce离子在较高温度时的平均磁矩μB以及在温度降低时被传导电子自旋屏蔽过程的影响.     

溶胶-凝胶法制备Polyme/MS/SiO2(M=Pb,Cd)复合纳米材料

采用溶胶－凝胶结合水热结晶技术,可成功把高聚物引入MS－SiO2网络结构。合成一种新型的有机－无机硫化物即Polymer/MS/SiO2(M=Pb,Cd)复合纳米材料,其中聚甲基丙烯酸甲酯或聚丙烯酰胺等高聚物的引入将有效地防止无机粒子团聚,控制粒子尺寸,前者还能形成核－壳结构复合粒子。作者还详细讨论了该复合纳米材料的热分析,结果表明,聚合物的存在提高了原有MS－SiO2(M=Pb,Cd)材料的热稳定性。     

利用拉曼技术判定氧化物和半导体纳米颗粒的尺度分布(英文)

Thiscontributionreportsonapplicationof low-wavenumberRamanscatteringonacoustical vibrationalmodesofnanoparticles.Theoretical backgroundaswellastheexperimentalresultsin determinationofoxideandsemiconductorparticle sizedistributionwillbepresented.Nanocrysta…     

MS(M＝Ca,Sr等)的化学稳定性分析

本文讨论了碱土硫化物的化学稳定性与晶化程度的关系,指出材料合成的反应机理是影响材料性能的一个关键因素.     

钛酸铅纳米颗粒的形成机理(英文)

本文报导了采用以下三种不同反应物形成钛酸铅纳米颗粒的机理。 1 ,铅 -钛共沉淀物 ;2 ,高能球磨后的铅 -钛共沉淀物 ;3 ,氧化铅和氧化钛的混合物。实验结果表明 ,在众多因素中 ,存在于氧化钛中的钛 -氧八面体对钛酸铅的形成起到了主要的影响。主要表现在 :已存在钛 -氧八面体的反应物可以直接形成钛酸铅 ,而没有钛 -氧八面体的反应物在形成钛酸铅之前会形成一种亚稳态的中间相。该亚稳相在有关钛酸铅的研究中首次被发现和报导。此外 ,本文还报导了球磨过程中 ,不同的球磨时间对钛酸铅的形成过程以及形成后钛酸铅颗粒的均匀性和尺寸的影响     

C(膜)/Si(SiO2)(纳米微粒)/C(膜) 的光致发光性质研究

用直流辉光溅射法结合真空镀膜法制备出了一种“多层三明治结构”的光致发光材料—C(膜 ) /Si(SiO2 ) (纳米微粒 ) /C(膜 )夹层膜 ,然后分别在 40 0、6 5 0和 75 0℃退火 1h .在波长为 2 5 0nm的紫外光激发下 ,刚制备出来未经退火处理的样品具有一个在 398nm (3.12eV)处的紫光宽带PL1峰 .在 6 5 0℃退火后 ,又出现了一个在 36 0nm (3.44eV)附近的PL2 峰 .PL1和PL2 峰形状和峰位与退火温度和激发波长无关 ,但强度却与退火温度和激发波长密切相关 .结合形态结构分析可知 ,紫光PL1峰可用量子限制 -发光中心 (QC LCs)模型进行解释 :即光激发发生在SiO2 微粒内部 ,而光发射源于SiO2 与Si界面上的缺陷中心 .紫外荧光PL2 峰则源自SiC内部的电子 空穴复合发光     

C(膜)/Si(SiO2)(纳米微粒)/C(膜)热处理的形态及结构分析

用直流辉光溅射＋真空镀膜法制备了一种新型结构的硅基纳米发光材料－C（膜）／Si（SiO2)(纳米微粒）／C（膜）夹层膜,并对其进行了退火处理,用TEM,SEM,XRD和XPS对其进行了形态结构分析,TEM观察表明：Si(SiO2)纳米微粒基本呈球形,粒径在30nm左右,SEM观察表明：夹层膜样品总厚度约为50um ,膜表面比较平整,致密,400度退火后,样品表面变得凹凸不平,出现孔状结构;650度退火后,样品表面最平整,致密且颗粒均匀,XRD分析表明：制备出的夹层膜主要由SiO2和Si 组成,在C原子的还原作用和氧气的化作用的共同作用下,SiO2和Si含量随加热温度的升高而呈现交替变化;400度时,C的还原作用占主导地位,SiO2几乎全部被还原成了Si,此时Si含量最高;400－650度时,氧化作用占主导地位,Si又被氧化成SiO2,Si 含量降低,SiO含量逐渐上升,在650度达到最高,XS分析表明：在加热过程中,C原子逐渐扩散进入Si(SiO2)_微粒层,在650度与Si反应生成了新的SiC。     

A layered antiferromagnetic semiconductor EuMTe3 (M = Bi,Sb)

We synthesized ternary tellurides EuMTe₃ (M = Bi, Sb) using a low‐temperature flux method. These compounds crystallize in the P_mmn space group with layered structure. A superstructure modulation along the b‐axis was observed. Physical property measurements revealed that these compounds are antiferromagnetic semiconductors. Finally, a strong spin–orbit coupling with possible novel quantum interference between localization and weak antilocalization effects was suggested in the present system. (© 2015 WILEY‐VCH Verlag GmbH &Co. KGaA, Weinheim)     

Synthesis and structural,magnetic characterization of Zn(Mn)O diluted magnetic semiconductor

The bulk samples with nominal composition Zn_1−x Mn_x O [x = 5% and 7%] were synthesized at 930 °C by Standard Solid State Reaction method. The structural analysis reveals the single phase nature. The Topography study indicates the distribution of the particles. Magnetic property was affirmed by Vibrating Sample Magnetometer, Zn_1−x Mn_x O (with x = 5%), low concentration of dopant shows good ferromagnetism compared to high concentration in Zn_1−x Mn_x O (with x = 7%).     

Investigation of the EPR parameters and local structures for Cu2+ in Bis(l-asparaginato) M(II) catalysts (M=Zn,Cd, Mg)

The electron paramagnetic resonance (EPR) parameters (g factors and hyperfine structure constants) for Cu²⁺ in Bis(l-asparaginato) M(II) catalysts (M=Zn, Cd, Mg) are theoretically investigated using the high order perturbation formulas of these parameters for 3d⁹ ions in orthorhombically elongated octahedra. Ligand orbital and spin–orbit coupling contributions are included from the cluster approach in view of strong covalency. The ligand octahedra (i.e., [CuO₄N₂]^12? clusters) are found to experience axial and perpendicular local bond length variations Δ (≈0.19–0.25 Å) and δ (≈0.12–0.14 Å) due to the Jahn–Teller effect and size mismatch, which are dissimilar to those of host M²⁺ sites in pure compounds. The theoretical EPR parameters based on the above local structures show good agreement with the observed values, and some improvements are achieved as compared with those in the previous work. The local structures of these centers are discussed.     

Optical properties of layered III–VI semiconductor γ-InSe:M (M=Mn,Fe, Co,Ni)

Indium selenide belongs to layered III–VI semiconductors with highly anisotropic optical and electronic properties. Energy gap of 1.32 eV makes this material very attractive for solar energy conversion. We investigated the influence of 1% 3-d transition metals M=Mn, Fe, Co, Ni, used as dopants, on energy levels of InSe:M in the range 1.4–6.5 eV and especially in the range of energy gap <1.4 eV by means of ellipsometric measurements. It was concluded that at ambient temperature foregoing dopants, all divalent, with 4s² valent electrons, in the similar way influenced on blue-shift of energy levels in valent zone, but did not influence on the fundamental energy gap. Photoluminescence measurements confirmed blue-shift of the valent zone energy levels and an existence of deep impurity levels.     

环式M(SO2)(M=Zn, Cd)分子及其阴离子的基质隔离红外光谱和密度泛函理论计算

激光溅射锌和镉原子与SO₂分子反应的低温基质隔离红外光谱实验表明,在氩和氖的惰性基质中,形成了环式M(SO₂)分子及其阴离子M(SO₂)^- (M=Zn, Cd)．相关同位素(³⁴SO₂和S¹⁸O₂)替代实验及密度泛函理论计算均证实了这一结果．此外,自然电荷布居分析表明电子从金属锌和镉的s轨道转移到了SO₂配体上形成了M⁺(SO₂)^-“离子对”复合物,且该分子中的Zn-O键以及Cd-O键均表现出强的极化共价性．而Hg原子在与SO₂反应中所表现出来的惰性可由其较强的相对论效应所致的6s价电子层收缩与高电离电位得以解     

Pressure dependence of the electric field gradient in Sb and Sb1−x M x (M=ln,Zn, Ge,Pb, Cd,Sn) at the site of111Cd

Using the¹¹¹Cd-TDPAC (time differential perturbated angular correlation) method, the pressure dependence of the electric field gradient (EFG) in Sb and Sb_1–x M _x (M=ln, Zn, Ge, Pb, Cd, Sn) was investigated. The application of a phenomenological ansatz for the parametrisation of the pressure and temperature dependence of the EFG made it possible to combine temperature data gained in former studies [1], [2] with the pressure dependent data presented in this paper. The resulting pressure dependence of –2±0.2 MHz/kbar is shown to be independent of concentration and element of admixture. Results for the volume and explicit temperature dependence agree with existing information on the mixed system Sb_1–x M _x (M=ln, Zn, Ge, Pb, Cd, Sn); the investigation of the EFG in Sb_1–x–y M _x Pb _y showed that the resulting EFG may be interpreted as the weighted sum of the individual contributions of the two metals.This paper is dedicated to Prof. Dr. W. Kreische on the occasion of his 60th aniversary on 02.02.1995