Ultrarotdurchlässigkeit und Struktur abschreckend kondensierter Schichten von PbS,PbSe und PbTe

Thin films of the lead chalcogenides PbS, PbSe and PbTe are condensed from the vapor onto substrates at low temperature. After condensation and during heating the infrared transmission between 0.8 and 18 μ is measured. Debye-Scherrer-diagrams also are sketched for investigating the structure of the layers. After condensation at 20° K the thin films are amorphous. Depending on the conditions of evaporation the layers crystallize at 83° K or at 115° K (PbS at 135° K) into the normal structure of NaCl-type. During crystallisation the infrared absorption edge moves to longer wavelengths. The high amount of covalent bond seems to be essential for the appearence of the amorphous phase when the substances are condensed on a substrate at low temperature.     

Ferromagnetismus von amorphem Eisen

In a previous paper a method has been described to produce thin films of amorphous iron by simultaneous condensation of iron and small additions of oxygen, silicon, or germanium onto a substrate at 20 °K. During annealing the amorphous films crystallize within a narrow range of temperature. In this paper the magnetic properties of these films are investigated. By a new lowtemperature ?gnetometer the magnetization curves can be registered for the different states of annealing. It results that even in the amorphous state iron is ferromagnetic. Below a critical concentration of the oxygen, silicon, or germanium admixtures the magnetic moment of the iron atoms is smaller and the coercive force is greater in the amorphous than in the crystalline structure. Above that concentration the magnetic moments in the two structures are equal, whereas the coercive force of the amorphous films is smaller than that of the crystalline ones. The results are explained by a concentration depending short range order in the amorphous films.     

Zur Struktur dünner,bei tiefer Temperatur kondensierter Salzschichten

Thin films of binary systems KCl/TlCl and RbCl/TlCl are condensated onto a substrate at low temperature (quenching condensation). Debye-Scherrer-Photographs are taken immediately after condensation and during annealing. After condensation at 20 ?K the films have a high degree of disorder, under certain conditions the films are forced even in an amorphous state. CsCl-type structure is found at high concentrations of TlCl, the films exhibit NaCl-type structure with increasing concentrations of KCl and RbCl. Diagrams of the frozen-in states of the condensated films are compared to the usual equilibrium diagrams of the binary systems.     

Study of thin Ge films with amorphous and nanocrystalline phases via the techniques of EXAFS spectroscopy and AFM

The local atomic structure and surface morphology of thin semiconductor films of Ge have been studied via extended X-ray absorption fine structure spectroscopy and atomic force microscopy. The films have been obtained by thermal evaporation of a material in an ultrahigh vacuum at different substrate temperatures. The films contain both amorphous and nanocrystalline phases. The percentage of the phases depends on the condensation temperature. The classical linear dependence of grain sizes on condensation temperature T is violated at T=100°C.     

Röntgenographische und optische Untersuchungen aufgedampfter Schichten aus Erdalkalichalkogeniden

Thin films of chalcogenides of the alkaline earth metals evaporated by electron bombardment are condensed on to a substrate at low temperature (quenching condensation). Debye-Scherrer-diagrams are taken immediately after condensation and during annealing. Moreover, the fundamental optical absorption is measured in the range between 3 and 6 eV. After condensation at 20° K the films have a high degree of disorder which decreases very slowly with increasing temperature. MgS, MgSe, and MgTe are forced even in an amorphous state. After annealing MgS and MgSe crystallize in a new modification, which can be described by a hexagonal lattice withc/a=1,6. It changes very slowly into the stable NaCl-lattice. The new structure can be explained by the ratio of the ionic radii, the appearence of the amorphous phase by the great polarization of the ions.     

Messung der spezifischen Wärme von abschreckend kondensierten Indium-, Blei- und Wismut-Schichten bei tiefer Temperatur

Thin metal films are evaporated onto a cooled Be-foil at 25–32 °K in high vacuum. After condensation the films have a large degree of disorder. The specific heat is measured in the temperature range from 5–8 °K after condensation and after annealing. No differences in the specific heat are found for disordered and annealed In- and Pb-films. The specific heat of amorphous Bi-films, however, is 1.7 times larger than that of crystalline films. The results are discussed together with investigations of disordered films by superconducting tunneling.     

电子束蒸发制备HfO2高k薄膜的结构特性

使用高真空电子束蒸发在p型Si（100）衬底上制备了高k HfO2薄膜.俄歇电子能谱证实薄膜组分符合化学配比；x射线衍射测量表明刚沉积的薄膜是近非晶的，高温退火后发生部分晶化；原子力显微镜和扫描电子显微镜检测显示在高温退火前后薄膜均具有相当平整的表面，表明薄膜具有优良的热稳定性；椭偏测得在600?nm处薄膜折射率为2.09；电容电压测试得到的薄膜介电常数为19.这些特性表明高真空电子束蒸发是一种很有希望的制备作为栅介质的HfO2薄膜的方法. 关键词： 高k薄膜 HfO2 电子束蒸发     

电子束蒸发制备HfO_2高k薄膜的结构特性

使用高真空电子束蒸发在p型Si(1 0 0 )衬底上制备了高kHfO2 薄膜 .俄歇电子能谱证实薄膜组分符合化学配比 ;x射线衍射测量表明刚沉积的薄膜是近非晶的 ,高温退火后发生部分晶化 ;原子力显微镜和扫描电子显微镜检测显示在高温退火前后薄膜均具有相当平整的表面 ,表明薄膜具有优良的热稳定性 ;椭偏测得在 6 0 0nm处薄膜折射率为 2 0 9;电容 电压测试得到的薄膜介电常数为 1 9.这些特性表明高真空电子束蒸发是一种很有希望的制备作为栅介质的HfO2 薄膜的方法     

Eigenschaften von Ag2Se-Schichten

Thin films of Ag₂Se are condensed onto a substrate at low temperature. The infrared-transmission and the electrical resistivity are measured after condensation and during annealing and Debye-Scherrer-diagrams are taken. After condensation at 80° K the Ag₂Se-films are amorphous. At 150–170° K they crystallize in a cubic structure. This structure corresponds to a high-temperature modification, which in thermodynamic equilibrium exists only above 133° C.     

Synthesis and characterization of palladium nanoislands on the silicon surface

Samples representing a system of Pd nanoparticles on a Si surface is obtained. The metal is deposited onto the substrate by thermal evaporation in vacuum. The system of nanoparticles is formed using a thin screen located at an angle to the substrate and by vacuum annealing of ultrathin continuous palladium films. The chemical composition of the deposited substance is studied by Auger electron spectroscopy. The size and topology of the islands on the surface is established by scanning electron microscopy.     

The microscope structures of amorphous phosphorus

The microscopic structures of thin films of amorphous phosphorus have been investigated by Raman scattering. The thin films were deposited by vacuum evaporation at substrate temperatures T_s between 300 and 510K. The Raman spectra of the films were compared with vibrational spectra of different allotropes of phosphorus: orthohombic black P, bulk amorphous red P and Hittorf's P. The structure of the films with T_s ? 300K is built up of double layers similar to those of orthorhombic black P. For T_s?510K the thin films have a structure similar to bulk amorphous red P based on the pentagonal tubes of Hittorf's P. A continuous transformation from one structure to the other is indicated by the Raman spectra of the films at intermediate T_s. The Raman measurements support early determinations of the structures of amorphous phosphorus inferred from radial distribution functions.     

Growth and properties of PbTe films on porous silicon

The structural and electrical characteristics of vacuum deposited PbTe films on Si substrate with buffer porous silicon (PS) layer were investigated. Auger electron spectroscopy, electron and optical microscopy data have shown the absence of cracks, pores, metal and chalcogen microinclusions. A mosaic structure with a grain size of 20–60 μm was detected by selective chemical etching and acoustic microscopy methods. The investigations of X-ray diffraction and X-ray pole figures showed that grains have [100] orientation along the growth direction. The cooling–heating (300–77–300 K) cycles of multilayer PbTe/sublayer/Si structures did not lead to the processes of peeling or appearance of cracks. It was found that thick amorphous layers on a PS surface change the nature of PbTe films growth.     

退火温度对a-Se0.70Ge0.15Sb0.15薄膜的结构和光学性质的影响

研究了退火温度对Se0.70Ge0.15Sb0.15薄膜的影响.通过热蒸发技术,在300K温度下将大块无定形Se0.70Ge0.15Sb0.1s沉积在石英和玻璃衬底上.研究发现,未经过退火处理的薄膜结构和在300K,1.33×10-5Pa下退火1小时后的薄膜结构都是无定形结构,而在同样气压470K温度下退火1小时的薄膜有结晶现象.通过在300 2 500nm范围内垂直入射光方向上透射率和反射率的测试,研究了薄膜的一些光学参数,如消光系数(k),折射系数(n)和吸收系数(a).研究发现,n和k同热处理温度有关.通过光学数据的分析,得到了不同条件下薄膜的间接带隙宽度(Enong),未经过热处理薄膜的Enong是1.715±0.021eV,300K下退火薄膜的Enong是1.643±0.021eV,470K下退火的Enong是1.527±0.021eV.退火温度降低了带隙宽度Enong,但增加了带尾eo这种效应可以根据Mott和Davis提出的多晶体系中态密度来解释.     

Ellipsometric in situ measurements during deposition of amorphous CuxSn100−x films

Amorphous metallic films are produced by quench condensation onto a 4K cold Si substrate under ultra high vacuum conditions. During evaporation the film growth is recorded in situ ellipsometrically. At the same time the mass of the film is measured with quartz microbalances. It is shown that the dielectric constants are dependent on film thickness. Different film models for evaluating the ellipsometric measurements are used and tested. The influence of porosity and interface roughness is taken into account. The dependence of mass density on thickness is mainly understood in terms of island growth. The dependence of the dielectric constant on concentration is discussed with respect to the Faber-Ziman theory.Dedicated to Prof. Dr. G. von Minnigerode on the occasion of his 60th birthday     

电子束蒸发在Si衬底上制备MgB2超导薄膜

利用电子束蒸发法在 Si(111)衬底上制备了 Mg B2 超导薄膜。首先在衬底上按照 1∶ 2的原子比交替蒸发 Mg和 B,所形成的夹层先驱膜在 15 0 Pa99.99% Ar气氛下进行原位热处理 6 30℃× 30 m in。实验发现超导薄膜在正常态下无半导体电阻特性 ,超导起始转变温度为 2 4 .7K,零电阻温度为 16 .5 K。     

Raman spectroscopy of amorphous silicon subjected to laser annealing

The effect of laser radiation power on the Raman spectra of amorphous silicon obtained by electron-beam evaporation has been revealed. The formation of nanocrystalline inclusions in the amorphous matrix under exposure to a laser with a power of more than 2.5 mW is established by Raman spectroscopy and photoluminescence. The influence of the fabrication conditions (substrate temperature and annealing in a vacuum) of source amorphous silicon films on the formation of nanocrystalline inclusions formed by subsequent laser treatment has been investigated. The features of silicon nanocrystal formation in cases when the original amorphous silicon film is obtained at a substrate temperature of ∼250°C have been revealed. These features may be associated with the presence of silicon-silicon multiple bonds.     

Messung der Fehlordnungsenergie an abschreckend kondensiertem Kupfer bei tiefer Temperatur

Copper films are produced by quenching condensation on a substrate at low temperature. A stored energy release of 216 cal/mole and a resistivity decrease of 1.8μΩcm are observed during annealing from 20 to 60 °K. In this temperature range the recovery of the films is described by a crystallisation of highly disordered material between small crystallites, which are produced during condensation. About 14 atomic-% of the whole film substance take part in this process. The stored energy-resistivity ratioE/Δ? found is 1.9 cal/g/gm/gWcm in the whole temperature range from 20 to 60 °K. This value is in good agreement with the stored energy measurements on neutron-bombarded copper.     

Struktur und ultrarote Gitterschwingung von CaF2 und LiF

Thin films of CaF₂, LiF and LiF +20% KF are condensed on to substrates at 20 °K. Immediately after condensation and after annealing to 373 °K the infrared absorption is measured between 15 and 43 microns. Also Debye-Scherrer-diagrams are taken for investigating the structure of the layers. After condensation at 20 °K LiF has a high degree of disorder, CaF₂ and LiF+20% KF show amorphous phases. The infrared lattice vibration of such films is shifted to shorter wavelenghts.     

采用Si薄膜的光子计数成像系统性能的研究

在陶瓷基底上利用电子束蒸镀方法制备了Si薄膜,用作感应读出方式光子计数成像系统的电荷感应层,并研究了薄膜的结构特征和表面形态.X射线衍射(XRD)测试和场发射扫描电子显微镜(FESEM)图像表明,沉积的Si薄膜为无定形态,由于陶瓷晶界的存在,薄膜较粗糙.搭建了相应的实验系统,对比了采用不同厚度Si薄膜时系统的空间分辨率、计数率、脉冲高度分布曲线等,发现薄膜的厚度对探测器的计数率影响较大.此外,实验还对比了采用相同电阻值的Si薄膜和常用的Ge薄膜时系统的性能.研究表明,采用Si薄膜时系统的畸变较小、计数率高     

Mössbauer effect investigation of amorphous FeZr interlayers formed by solid state reaction

Recent investigations claimed the complete amorphization of elemental FeZr multilayer films by solid state reaction during vacuum annealing. In the present study it is established by⁵⁷Fe conversion electron Mössbauer spectroscopy (CEMS) that annealing under ultrahigh vacuum conditions does not lead to complete amorphization: only a maximum thickness of ≈14 Å interfacial α-Fe is transfered into the amorphous phase between 620–660 K. This thin amorphous layer apparently acts as a diffusion barrier and prohibits further growth of the amorphous phase. The average composition of the amorphous interfacial layer was determined from the Mössbauer spectral parameters.