Atomic Precision Advanced Manufacturing for Ultraprecise 2D Bipolar Devices.
Abstract not provided.
Owen, James↗
Engineering topics
Fuchs, Ehud
Publications and source records attributed to Fuchs, Ehud.
Atomic precision imaging with an on-chip scanning tunneling microscope integrated into a commercial ultrahigh vacuum STM system
In this article, we replace the Z axis of the piezotube of a conventional Ultrahigh-Vacuum (UHV) Scanning Tunneling Microscope (STM) with a one-degree-of-freedom Microelectromechanical-System (MEMS) nanopositioner. As a result, a hybrid system is realized in which motions in the XY plane are carried out by the piezotube, while the MEMS device performs the Z-axis positioning with a smaller footprint and higher sensitivity. With the proposed system and a feedback loop, STM imaging is conducted on an H-passivated Si (100)-2×1 sample in a UHV condition, demonstrating that this on-chip STM is conducive to atomic precision scanning tunneling microscopy.
Engineering↗
Ultrafast method for scanning tunneling spectroscopy
A scanning tunneling microscope (STM) combines unique capabilities in imaging and spectroscopy with atomic precision, and it can obtain energy-resolved spectroscopic data with atomic resolution. In this paper, we utilize a recently proposed modification to the STM feedback control loop to acquire high quality d 2 I/dV 2 images. We have developed a constant differential conductance imaging method by closing the STM feedback loop with a high precision dI/dV measurement. In this mode, the tip’s vertical position is adjusted so as to keep the differential conductance constant during raster scanning of the surface. Based on this imaging mode, we propose a new technique to acquire fast and reliable scanning tunneling spectroscopy (STS) data simultaneously with the imaging.
47 OTHER INSTRUMENTATION↗
High signal-to-noise ratio differential conductance spectroscopy
The scanning tunneling microscope (STM) has enabled manipulation and interrogation of surfaces with atomic-scale resolution. Electronic information about a surface is obtained by combining the imaging capability of the STM with scanning tunneling spectroscopy, i.e., measurement of current-voltage (I/V) characteristics of the surface. We propose a change in the STM feedback loop that enables capturing a higher quality dI/dV image. A high frequency dither voltage is added to the bias voltage of the sample, and the fundamental frequency component of the resulting current is demodulated. The in-phase component of this signal is then plotted along with the X and Y position data, constructing the dI/dV image. Here, we show that by incorporating notch filters in the STM feedback loop, we may utilize a high-amplitude dither voltage to significantly improve the quality of the obtained dI/dV image.
42 ENGINEERING↗