Jae-Hong Kwon

Organic thin film transistors with polyvinyl alcohol treated dielectric surface

This is a report on a simple method for improving poly-4-vinylphenol (PVP) organic thin-film transistors (OTFTs). To decrease surface roughness so that we could form a larger grain size, we coated a polyvinyl alcohol (PVA) film onto the PVP dielectric layer. The effect of PVA treated gate dielectric surface modification has been examined and these organic transistors showed improved electrical characteristics with field effect mobility of 3.6 × 10−2 cm2 V−1 s−1 and a Ion/Ioff ratio of 2.11 × 105. The results demonstrate the possibility of a simple enhancement method through the process which uses a polymer thin film.

pH Sensor Using Carbon Nanotubes as Sensing Material

Carbon nanotube (CNT) integrated with biological functionalities is expected to be one of the most promising field in future biomedical applications. CNT material with prominent properties along with application of micro fabrication technology make possible enormous application potential sensors with high resolution, more accurate, higher sensitivity and micrometer size. One of these applications, introduced in this paper, is pH sensors using CNT as sensing material. Monitoring and evaluating the pH of the solution in a bioprocess is one of the key steps in the success of bioreactor operation. Our proposal based on the changes significantly in electrical property of CNT under different pH environment. This paper describes a method for designing a simple and fast response pH sensor employing single wall carbon nanotube (SWCNT) using a spray. The conductance and the typical amperometric response of SWCNT at room temperature at different hydroxyl ion concentrations were successfully demonstrated.

P-110: Dual-Layered Films Consisting of CNT and Conducting Polymer Fabricated by Micro-Contact Printing for Flexible Electrodes

We report a CNT/conducting polymer dual-layered films (CPDFs), which has ∼1000Ω/sq resistance and ∼93% transmittance, self-aligned with a precision of 20μm by micro-contact printing. In addition, a potential usage of the CPDFs as a transparent electrode for the application in flexible devices including organic thin film transistor (OTFT) is demonstrated.

Development of single walled-carbon nanotubes based pH sensor using ultra-precision spray method

Recent studies demonstrated the ability of carbon nanotube (CNT) to promote electron transfer reactions of important compounds and to impart higher stability onto electrochemical sensors. CNT-based sensors measured by hydroxyl radical concentration or pH value suggest great promise for biosensors. This paper describes a new method for fabricating a very simple and inexpensive pH sensor compose of single walled-carbon nanotubes (SW-CNTs) using an ultra-precision spray. CNT-based sensor shows pH sensitivity in buffer solution at different pH range. Our experimental results show the sensor responses to pH buffer solution and the conductance of depends on the pH values. These results support application possibility of SW-CNTs based pH sensor for mass production.

Study of sand blaster dry etched glass wafer surface for micro device package

In this paper, glass cap wafer for MEMS device package is fabricated by using sand blaster dry etcher and Its surface is studied. The surface of dry etched glass is analyzed by using SEM, and many glass particles and micro cracks are observed. If these kind of particles were dropped from glass to the surface of device, It would make critical failure to the operation of device. So, several cleaning and etching methods are induced to remove these kinds of dormant failure mode and optimized condition is found out.