Byong Man Kim

Fabrication of a Josephson junction using an atomic force microscope

A Josephson junction was fabricated by inducing a selective surface modification on a YBa2Cu3O7−y strip with an atomic force microscope (AFM). The surface modification in the field of conductive AFM tip results in the controlled growth of protrusions across the entire strip. By properly regulating the extent of AFM modification, we achieved a Josephson junction. The self-radiation power of about 50 pW at a resonant frequency of 22 GHz was detected from this junction, which is in excellent agreement with the Josephson frequency-voltage relationship.

Scanning probe charge reading of ferroelectric domains

A scanning probe charge-detection technique based on direct piezoelectric effect is demonstrated to read alternating bit polarizations in a ferroelectric media The bit signal is generated by spatially modulating charges interacting with a probe tip scanning in contact with the media. A periodicity of the bits is used with an appropriate scan speed to modulate the signal frequency. A signal-to-noise ratio of 10 dB has been achieved for a contact force of 100 nN. The modulation of the bit signal frequency into the 2 kHz data rate is achieved by coupling 0.4 μm spacing between alternating polarizations with scanning speed of 1.6 mm/s.

In-Situ Electrical Study of a Reversible Surface Modification and a Nanomachining of Gold Microstrips by the Voltage-Biased Atomic Force Microscope Tip in Air

We report on a reversible polymerization of ambient carbonaceous deposits on the surface of gold microstrips by means of a voltage-biased atomic force microscope tip in air. This approach is found capable of controlled writing, erasing, and rewriting of carbon-rich deposits with sizes in nanometer regime. Physical mechanism for this reversible patterning is proposed to be the current-induced electrochemical process. In addition, we introduce a novel nanomachining technique based on an electric field enhanced cutting process.

Nanochip: A MEMS-Based Ultra-High Data Density Memory Device

The paper provides an overview of a probe storage device development. The main results are related to successful development of ferroelectric memory, MEMS micro-mover with large range of motion and an array of cantilevers with sharp tips (read–write heads), demonstrating wear resistance of the tips, integration of memory material into the MEMS process, integration of MEMS cantilever process with CMOS, development of analog front end electronics, including read channel and servo system, and a controller for a storage device.

Reversible patterning of ambient carbon-rich deposits on a gold surface by means of a voltage-biased atomic force microscopy

Abstract We report on a reversible patterning of ambient carbon-rich deposits on a gold surface by using a voltage-biased atomic force microscope tip in air. This approach is capable of controlled writing, erasing, and rewriting of carbon-rich deposits with sizes in nanometer regime. Physical mechanism for this reversible patterming is proposed to be the current-induced electrochemical process.