Suche nach „[Y.] [Ji]“ hat 2 Publikationen gefunden
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    NachhaltigF: Elektrotechnik und MedientechnikI: IQMA


    S. Chen, L. Jiang, M. Buckwell, X. Jing, Y. Ji, E. Grustan-Gutierrez, Günther Benstetter, F. Hui, Y. Shi, M. Rommel, A. Paskaleva, W. Ng, A. Mehonic, A. Kenyon, M. Lanza

    On the Limits of Scalpel AFM for the 3D Electrical Characterization of Nanomaterials

    Advanced Functional Materials, vol. 28, no. 52


    DOI: 10.1002/adfm.201802266

    Abstract anzeigen

    Conductive atomic force microscopy (CAFM) has been widely used for electrical characterization of thin dielectrics by applying a gentle contact force that ensures a good electrical contact without inducing additional high‐pressure related phenomena (e.g., flexoelectricity, local heat, scratching). Recently, the CAFM has been used to obtain 3D electrical images of thin dielectrics by etching their surface. However, the effect of the high contact forces/pressures applied during the etching on the electrical properties of the materials has never been considered. By collecting cross‐sectional transmission electron microscopy images at the etched regions, it is shown here that the etching process can modify the morphology of Al2O3 thin films (producing phase change, generation of defects, and metal penetration). It is also observed that this technique severely modifies the electrical properties of pSi and TiO2 wafers during the etching, and several behaviors ignored in previous studies, including i) observation of high currents in the absence of bias, ii) instabilities of etching rate, and iii) degradation of CAFM tips, are reported. Overall, this work should contribute to understand better the limitations of this technique and disseminate it among those applications in which it can be really useful.

    NachhaltigF: Elektrotechnik und MedientechnikI: IQMA


    Y. Ji, H. Fei, Y. Shi, V. Iglesias, D. Lewis, N. Jiebin, S. Long, M. Liu, Alexander Hofer, Werner Frammelsberger, Günther Benstetter, A. Scheuermann, P. McIntyre, M. Lanza

    Characterization of the photocurrents generated by the laser of atomic force microscopes

    Review of Scientific Instruments, vol. 87, no. 8


    DOI: 10.1063/1.4960597

    Abstract anzeigen

    The conductive atomic force microscope (CAFM) has become an essential tool for the nanoscale electronic characterization of many materials and devices. When studying photoactive samples, the laser used by the CAFM to detect the deflection of the cantilever can generate photocurrents that perturb the current signals collected, leading to unreliable characterization. In metal-coated semiconductor samples, this problem is further aggravated, and large currents above the nanometer range can be observed even without the application of any bias. Here we present the first characterization of the photocurrents introduced by the laser of the CAFM, and we quantify the amount of light arriving to the surface of the sample. The mechanisms for current collection when placing the CAFM tip on metal-coated photoactive samples are also analyzed in-depth. Finally, we successfully avoided the laser-induced perturbations using a two pass technique: the first scan collects the topography (laser ON) and the second collects the current (laser OFF). We also demonstrate that CAFMs without a laser (using a tuning fork for detecting the deflection of the tip) do not have this problem.