Papers by Keyword: Scanning Probe Microscope

Abstract: In this study, we tried to develop the scanning near-field polarization microscope (SNPM) and challenge to observe magnetization of the magnetic nanodot in the arrays. The CoPt dot arrays with a size of 25 nm and a pitch of 150 nm were adopted. The nanodots change contrast after changing the direction of the external magnetic field. This implied that our prototyped SNPM system had the resolution of less than 25 nm. So, it is demonstrated that SNPM is an effective tool for the observation of magnetization of the magnetic nanodot on the nanometer scale.

Abstract: An adjustable inertia balance support is proposed to counterbalance the inertial force from the actuators for high performance scanning probe microscope. The adjusting method is based on voltage proportion control. In contrast with traditional method that adding or removing mass, it is very convenient to adjust to minimize the inertial force transmitted to the supporting base. It may have a promising application on the current inertia balance support structure, which is used in some high-speed scanning probe microscope. What is more, it has a very good compatibility with current structure.

Abstract: In this work, the influences of plasma pre-treatment on polyethylene terephthalate (PET) substrate to the properties of ZnO thin film have been carried out. ZnO thin films were successfully grown on PET substrate by spin coating method. In order to study the effects of plasma pre-treatment, a comparison of treated and untreated condition was employed. Water contact angle measurement had been carried out for PET wettability study prior to ZnO thin film coating. Morphology study of ZnO thin film was performed by scanning probe microscope (SPM). Besides, optical study of the ZnO thin film was done by using UV-vis spectrophotometer. All the measured results show that plasma pre-treatment of PET substrate plays an important role in enhancing the wettability of PET and optical properties of the ZnO thin films. In conclusion, pre-treatment of PET surface is essential to produce higher quality ZnO thin film on this particular substrate in which would pave the way for the integration of future devices.

Abstract: This research applied a stylus probe without balance and lever arm as in the previous design of a contact-force-controlled Scanning Probe Microscope (SPM) system. The controller integrated both Ziegler-Nichols-based and intelligent fuzzy methods; thus the systems relative stability can be reserved under the nominal conditions. In addition, one can see that both hysteresis and parameter variation effects of the force actuator can be reduced. Comparing the results with the traditional Ziegler-Nichols-based controller by simulation, one can see that the proposed systems are much more robust.

Abstract: The morphology of typical carbon materials including granular graphite, carbon nanotubes and graphenes was observe by scanning probe microscope (SPM). When water is used as the dispersants for preparing observing samples of the above carbon materials, the typical morphology characteristics of spherical graphite, curved carbon nanotubes and graphene sheets are distinctly exhibited by SPM. However, for graphene materials, when alcohol or dimethylformamide (DMF) is used as dispersants, the quality of SPM images becomes poor. The interaction between the dispersants and materials should be responsible for these observation results.

Abstract: The development of the various scanning probe microscopy techniques has revolutionized the study of surface structure up to atomic scale. Among these techniques, Nanoeducator as scanning force microscope or SFM has been developed to allow the accomplishment of various measuring techniques both for scanning tunneling microscope (STM) and non-contact atomic force microscope (AFM). However, there is no exact guidance how to fabricate cantilever to gather the good image. In order to achieve the better cantilever for students, this paper emphasizes on tip’s processing by altering etching length parameter as tip plays an important role to achieve better quality image during scanning operation. This paper also provides a guide for undergraduate student to know better about this machine as well as the principle behind it for them to acquire better quality image for their works. It was found that the number of turning of tungsten and etching time could produce good tip of cantilever. It is recommended for lecturers, students and technician to consider about turning and time of etching to produce a better tip of cantilever in Nanoeducator.

Abstract: Pattern size controllability of SPM-based nano-lithography especially in vertical direction was improved using in-situ height and depth measurements at the processed point. The transient oxide growth was monitored by light transmission (depth of the oxide in sample metal surface) and topographical signals measurements obtained from a scanning near-field optical microscope. First, we investigated oxidizing rate limitation on titanium film. At the voltage rise faster than 10 V/sec, the depth growth didn’t follow the voltage change in spite of immediate upheaval growth. This result suggested the rate determining of reactive chemicals transport in the titanium oxide. Next, we discovered improvement in the process stability on intractable materials (e.g. iron group elements or noble metals; manganese in this paper) by using thin cap layer of titanium. As the result, the oxidization reaction progressed moderately due to the facts that the oxide of the cap layer is electrical insulative and restriction of the permeability of the reactive chemicals (ingredients of the oxide) that were electrochemically generated at apex of the probe tip.

Abstract: A method to easily and economically manufacture more precise patterns compared with usual MEMS technique has been searched for. Under such circumstances, this research aims to clarify the formation of nano-scale protrusion structure produced by local anodic oxidation on Si wafer surface in expectation of the nano/micro mold production for nanoimprint lithography in future. In this report, the influences of contact width and distance between probe tip and Si wafer surface (distance between terminals) on the size and shape of protrusion patterns were examined in order to clarify the fundamental phenomena in local anodic oxidation. A scanning probe microscope equipped with a current measuring unit was utilized in local anodic oxidation experiments. As a result, it was confirmed that the size of generated protrusion structure became larger with increasing the contact width and became smaller with increasing the distance between probe tip and Si wafer surface. These facts will be useful in producing 3-D nanostructures in future.

Abstract: Scanning probe microscopy with conductive tips has been used to image the dielectric properties of ceramics with giant permittivity. In particular, measurements in impedance mode and of local resistivity allowed to image the permittivity map on polycrystalline materials. Such imaging allows to correlate the dielectric properties with the local sample structure and with defects inside the single grains of the polycrystalline ceramics. However, artifacts due to surface imperfections should be distinguished from bulk properties and eliminated.

Abstract: This paper shows a method of designing a nano-positioning planar scanner that can be used in a scanning probe microscope. The planar scanner is composed of flexure guides, piezoelectric actuators and feedback sensors. Furthermore, we used a motion amplifying mechanism in the piezoelectric actuator to achieve a large travel range. We theoretically determined the travel range of the total system and verified the range by using a program based on a finite element analysis. The maximum travel range of the planar scanner was greater than 120 μm. A planar scanner of an atomic force microscope can move samples with a few nm resolutions. To get stable AFM images of small feature samples, a closed loop control could not be used due to large random errors of the sensor. The orthogonality of a new planar scanner having a motion guide is measured and corrected by using a simple electronic circuit in the open loop scanning to reduce the scanner artifact.