AR原子力显微镜标准型(AFM)

液相条件下FM-AFM测试

Frequency modulation atomic force microscopy
FM-AFM is rapidly evolving as the technique of choice in the pursuit of high resolution imaging of biological samples in ambient environments. The enhanced stability afforded by this dynamic AFM mode combined with quantitative analysis enables the study of complex biological systems, at the nanoscale, in their native physiological environment. The operational bandwidth and accuracy of constant amplitude FM-AFM in low Q environments is heavily dependent on the cantilever dynamics and the performance of the demodulation and feedback loops employed to oscillate the cantilever at its resonant frequency with a constant amplitude. Often researchers use ad hoc feedback gains or instrument default values that can result in an inability to quantify experimental data. Poor choice of gains or exceeding the operational bandwidth can result in imaging artifacts and damage to the tip and/or sample. To alleviate this situation we present here a methodology to determine feedback gains for the amplitude and frequency loops that are specific to the cantilever and its environment, which can serve as a reasonable “first guess,” thus making quantitative FM-AFM in low Q environments more accessible to the nonexpert. This technique is successfully demonstrated for the low Q systems of air
Q 40 and water
Q1. In addition, we present FM-AFM images of MC3T3-E1 preosteoblast cells acquired using the gains calculated by this methodology demonstrating the effectiveness of this technique

石墨烯表面EFM研究

When a single-layer graphene
SLG is on SiO2 substrates, the charge exchange at their interface results in a dipole, which direction strongly depends on the contact potential difference between the SLG and the substrates. Due to the longer experimental charge screening length of SLG than its thickness, the charge redistribution imposes effective p or n doping to SLG films. The substrate-dependent doping of SLG films is further confirmed by Raman and electrical measurements. Also, the unique electronic structures of SLG films make them sensitive to the doping rather than effective gating from the SiO2 substrates

金刚石薄膜表面电学性能分析

The electrical conduction behavior of undoped ultrananocrystalline diamond
UNCD and its dependence on deposition temperature and chemical structure are presented. UNCD films were grown using a microwave plasma-enhanced chemical vapor deposition technique at deposition temperatures of 400 °C and 800 °C. The chemical structure of the UNCD films is characterized with several tools including: Elastic recoil detection analysis, Fourier transform infrared spectroscopy, electron energy loss spectroscopy, Raman spectroscopy, and environmental scanning electron microscope. The results show a higher content of sp2-bonded carbon for the 800 °C deposition samples
65% in comparison with the 400 °C samples
38%. In both kinds of films, the hydrocarbon bonds have the saturated sp3 structures, while there is lower hydrogen content in the 800 °C samples
8% than in the 400 °C samples
10%. For conduction properties, experiments are conducted using a probe station and conductive-atomic force microscopy. Experimental data show that the samples deposited at 800 °C are several orders of magnitude more conductive than the 400 °C samples. The conduction occurs primarily along the grain boundary for both types of samples. The conductivity of both types of films also shows field dependent nonlinear behavior. Both the Poole–Frenkel models and single and overlapping Coulombic potential models show that the conduction is directly correlated with the sp2 bond carbon density, and the role of the hydrocarbon bonds in the conduction path is formed by the network of the sp2 bonded carbon.

薄膜观察（thulium(III) 氧化物）

Thulium(III) oxide (Tm2O3) targets prepared by the polymer-assisted deposition (PAD) method were irradiated by heavy-ion beams to test the method’s feasibility for nuclear science applications. Targets were prepared on silicon nitride backings (thickness of 1000 nm, 344 mg/cm2) and were irradiated with an 40Ar beam at a laboratory frame energy of !210MeV (50 particle nA). The root mean squared (RMS) roughness prior to irradiation is 1.1nm for a !250nm (!220 mg/cm2) Tm2O3 target, and an RMS roughness of 2.0nm after irradiation was measured by atomic force microscopy (AFM). Scanning electron microscopy of the irradiated target reveals no significant differences in surface homogeneity when compared to imaging prior to irradiation. Target flaking was not observed from monitoring Rutherford scattered particles as a function of time.

针尖加强荧光显微镜

在本文中利用针尖加强效果对荧光小球进行了荧光成像，对比了激光偏振性对成像的影响以及外置的锁相放大技术对于成像的影响。作为一个好的针尖加强成像系统而言外置的锁相放大技术完全必不可少的。

原子力显微镜的基本物理知识

在本页中您可以看到基本所有原子力显微镜用到的物理公式和物理模型。其包括胡克定律、探针定标的种种公式、高次谐波的定义。