Study of Perylenetetracarboxylic Acid Dimethylimide Films by Cyclic Thermal Desorption and Scanning Probe Microscopy

Some results of studying the direct-current (DC) conductivity of perylenetetracarboxylic acid dimethylimide films by cyclic oxygen thermal desorption are presented. The microscopic parameters of hopping electron transport over localized impurity and intrinsic states were determined. The bandgap width and the sign of major current carriers were determined by scanning probe microscopy methods (atomic force microscopy, scanning probe spectroscopy, and photoassisted Kelvin probe force microscopy). The possibility of the application of photoassisted scanning tunneling microscopy for the nanoscale phase analysis of photoconductive films is discussed.     

光子扫描隧道显微镜的探测场

通过修改光子扫描隧道显微镜探测场的计算模型，推导出比较符合实际的探测场及透射系数的计算公式，并利用这一新计算公式在微机上进行了模拟计算，得到了一些过去未曾发现的现象，对光子扫描隧道显微镜的实际探测具有一定的指导意义。     

自组装高导电石墨烯薄膜的光谱特性表征

本文提出了一种石墨烯薄膜的自组装制备技术,获得了高导电、高透明的均匀石墨烯薄膜,并对其进行了参数测试和光谱特性研究。研究表明此方法制备的石墨烯薄膜具有杂质含量少、高导电、高透明、膜厚均匀可控等优点,其平均透过率达到80%,方阻最低可达到0.2Ω/sq,在透明电极和有机光电子学领域有重要应用前景。     

Experiment Researches on Active Fibre Probe for Scanning Near-field Optical Microscopy

ＥｘｐｅｒｉｍｅｎｔＲｅｓｅａｒｃｈｅｓｏｎＡｃｔｉｖｅＦｉｂｒｅＰｒｏｂｅｆｏｒＳｃａｎｎｉｎｇＮｅａｒｆｉｅｌｄＯｐｔｉｃａｌＭｉｃｒｏｓｃｏｐｙＺＨＡＮＧＧｕｏｐｉｎｇＭＩＮＧＨａｉＣＨＥＮＸｉａｏｇａｎｇＹＡＮＧＢａｏＸＩＥＪｉａｎｐｉｎ...     

Visualization and Characterization of Discontinuous Particle Films of Polystyrene by Atomic Force Microscopy

Discontinuous particle films of polystyrene (PS) with different molecular weights were prepared by the methods of spin coating (SPC) and droplet evaporation (DE) at room temperature on mica substrates. Visualization and characterization of these samples were performed by atomic force microscopy (AFM). The results showed that the dimensions of the particles in the films increased with molecular weight. The dimensions of the particles in the films derived from SPC exhibited better uniformity than those from DE. During the steps of particle film formation by SPC, the PS molecules gathered in large clusters at the early stage, then the polymer aggregates were separated or spun off, and more and more particles emerged, finally the clusters vanished and the particle film formed. The particles of the spin-coated film dewetted after annealing and numerous individual polymer chains appeared newly on the mica substrate.     

Graphene/Rh(111) Structure Studied Using In-Situ Scanning Tunneling Microscopy

Scanning tunnel microscopy(STM)is performed to verify if an Rh 'nails' structure is formed accompanying the graphene growing during chemical vapor deposition.A structure of a graphene island in an Rh vacancy island is used as the start.While the graphene island is removed by oxygenation,the variations of the Rh vacancy island are imaged with an in-situ high-temperature STM.By fitting with our model and calculations,we conclude that the best fit is obtained for 0%Rh,i.e.,for the complete absence of nails below graphene on Rh(111).That is,when graphene is formed on Rh(111),the substrate remains flat and does not develop a supporting nail structure.     

Heterojunction Effect in Weak Epitaxy Growth Thin Films Investigated by Kelvin Probe Force Microscopy

We investigate the heterojunction effect between para-sexiphenyl （p-6P） and copper phthalocyanine （CuPc） using Kelvin probe force microscopy. CuPc films are grown on the inducing layer p-6P by a weak epitaxy growth technique. The surface potential images of Kelvin probe force microscopy indicate the band bending in CuPc, which reduces grain boundary barriers and lead to the accumulation of holes in the CuPc layer. The electrical potentiM distribution on the surface of heterojunction films shows negligible grain boundary barriers in the CuPc layers. The relation between band bending and grain boundary barrier in the weak epitaxy growth thin films is revealed.     

Bi-Substituted Iron Garnet Films for Thermomagnetic Recording,Photonics, and Plasmonics: Optimization of Synthesis Conditions Using Scanning Probe Microscopy

Technical Physics - We present the results of studies on the optimization of the synthesis of Bi-substituted iron garnet (Bi : IG) films by liquid-phase epitaxy and vacuum deposition followed by...     

Study of CsPbBr3 Nanocrystals and Their Agglomerates by Combined Scanning Probe Microscopy and Optical Spectrometry

Optics and Spectroscopy - The electric, piezoelectric, and optical properties of colloidally synthesized CsPbBr3 nanocrystals (NCs) are studied by combined scanning probe microscopy and optical...     

Archaeological Ceramics Studied by Scanning Electron Microscopy

The use of scanning electron microscopy combined with energy dispersive X-ray fluorescence analysis in studies of archaeological pottery is discussed. The methods are described and results of their application to studies of Precolumbian glossy black pottery from northern Peru are reported in some detail.     

Erratum to: Determination of the Electrical Resistivity of Vertically Aligned Carbon Nanotubes by Scanning Probe Microscopy

Technical Physics - An Erratum to this paper has been published: https://doi.org/10.1134/S1063784221080193     

Electrical Scanning Probe Microscopy: Investigating the Inner Workings of Electronic and Optoelectronic Devices

Semiconductor electronic and optoelectronic devices such as transistors, lasers, modulators, and detectors are critical to the contemporary computing and communications infrastructure. These devices have been optimized for efficiency in power consumption and speed of response. There are gaps in the detailed understanding of the internal operation of these devices. Experimental electrical and optical methods have allowed comprehensive elaboration of input–output characteristics, but do not give spatially resolved information about currents, carriers, and potentials on the nanometer scale relevant to quantum heterostructure device operation. In response, electrical scanning probe techniques have been developed and deployed to observe experimentally, with nanometric spatial resolution, two-dimensional profiles of the electrical resistance, capacitance, potential, and free carrier distribution, within actively driven devices. Experimental configurations for the most prevalent electrical probing techniques based on atomic force microscopy are illustrated with considerations for practical implementation. Interpretation of the measured quantities are presented and calibrated, demonstrating that internal quantities of device operation can be uncovered. Several application areas are examined: spreading resistance and capacitance characterization of free carriers in III-V device structures; acquisition of electric potential and field distributions of semiconductor lasers, nanocrystals, and thin films; scanning voltage analysis on diode lasers—the direct observation of the internal manifestations of current blocking breakdown in a buried heterostructure laser, the effect of current spreading inside actively biased ridge waveguide lasers, anomalously high series resistance encountered in ridge lasers—as well as in CMOS transistors; and free-carrier measurement of working lasers with scanning differential spreading techniques. Applications to emerging fields of nanotechnology and nanoelectronics are suggested.     

Local Piezoresponse and Thermal Behavior of Ferroelastic Domains in Multiferroic BiFeO3 Thin Films by Scanning Piezo-Thermal Microscopy

A dual probe, i.e., high resolution scanning piezo-thermal microscopy, is developed and employed to characterize the local piezoresponse and thermal behaviors of ferroelastic domains in multiferroic BiFeO3 thin films. Highly in- homogeneous piezoelectric responses are found in the thin film. A remarkably local thermal transformation across ferroelastic domain walls is clearly demonstrated by the quantitative 3w signals related to thermal conductivity. Different polarization oriented ferroelastic domains are found to exhibit different local thermal responses. The underlying mechanism is possibly associated with the inhomogeneous stress distribution across the ferroelastic domain wails, leading to different phonons scattering contributions in the BiFeO3 thin film.     

Near-Field Fluorescence and Topography Characterization of a Single Nanometre Fluorophore by Apertureless Tip-Enhanced Scanning Near-Field Microscopy

Tip-enhanced near-field fluorescence and topography characterization of a single nanometre fluorophore is conducted by using an apertureless scanning near-field microscopy system. A fluorophore with size 80hm is mapped with a spatial resolution of 10hm. The corresponding near-field fluorescence data shows significant signal enhancement due to the apertureless tip-enhanced effect. With the nanometre spatial resolution capability and nanometre local tip-enhanced effect, the apertureless tip-enhanced scanning near-field microscopy may be further used to characterize a single molecule by realizing the local near-field spectrum assignment corresponding to topography at nanometre scale.     

Improving Data Quality in Traditional Low-Dose Scanning Transmission Electron Microscopy Imaging

It has become very important to study and find optimal conditions for imaging electron-beam (e-beam) sensitive materials in scanning transmission electron microscopy under low electron-dose with high signal-to-noise ratio (SNR). Convergence and collection angles and electron-probe current are essential parameters. However, these parameters have rarely been discussed in a systematic way. In this paper, the illumination and collection conditions are optimized according to the resolution requirement of different materials by adjusting the condenser and intermediate lenses in a commercial transmission electron microscope. To demonstrate the significance of optimizing these parameters, two examples, zeolite MFI and metal–organic framework (MOF) MIL-101, are taken among the sensitive materials, with the most important electron incidences along the [010] and <110> directions, respectively. High SNR atomic resolution images of MFI are obtained with e-beam current as low as 0.50 pA, reaching information transfer for reflection up to 18 0 2 corresponding to d-spacing of 0.11 nm, close to the resolution limit of 0.098 nm from resolvable diffraction limit. MOF MIL-101 is characterized under an even lower e-beam 0.2 pA to avoid severe beam damage. High-quality annular dark and bright field images are obtained, which proves the wide applicability of this method on more e-beam sensitive materials.     

Thermal Properties of Materials Characterized by Scanning Electron-Acoustic Microscopy

A modified technique of scanning electron-acoustic microscopy is employed to determine thermal diffusivity of materials. Using the dependence of the electron-acoustic signal on modulation frequency of the electron beam, the thermal diffusivity of materials is characterized based on a simplified thermoelastic theory. The thermal diffusivities of several metals characterized by the modified scanning electron-acoustic microscopy are in good agreement with the referential values of the corresponding materials, which proves that the scanning electronacoustic microscopy can be used to characterize the thermal diffusivity of materials effectively. In addition, for micro-inhomogeneous materials, such as biological tissues, the macro-effective （average） thermal diffusivities are characterized by the technique.     

10 nm Spatial Resolution Fluorescence Imaging of Single Molecules by Near-Field Scanning Optical Microscopy Using a Tiny Aperture Probe

We demonstrate high-resolution fluorescence imaging of single molecules using near-field scanning optical microscopy (NSOM) with a tiny aperture probe for two different wavelengths in visible range in the illumination mode of operation. The spatial resolutions obtained at both excitation wavelengths were almost the same and the highest resolution realized was about 10 nm. To discuss the achievable resolution in aperture NSOM, we also employed a computer simulation by the finite-difference time-domain method for various aperture sizes and wavelengths. The resolution of 10 nm is predicted to be contributed by the single peak of localized near-field light around the rim of the aperture.