The joint research team of Kookmin University, Kyung Hee University, and University of California, Berkeley developed the laser hardening technique that can be applied to the molybden disulphide flexible transistors, and this result was selected as the back-inside cover article in the latest issue (volume of August 2014) of Nano Research that is a prestigious academic journal specialized in nanotechnology. This thesis suggested the procedure of laser hardening that is needed for the production of high-performance flexible transistors and through this, it introduced a possibility to apply molybden disulphide transistors in a variety of fields, such as TV/monitor/mobile phone and solar cell in use of transparent and flexible display.

Molybden disulphide is a semiconductor with 2-dimensional crystal structure similar to graphene. Since its transistor characteristic is superior to that of graphene, it is being highlighted as the next-generation graphene. However, it requires high temperature treatment in hundreds of degrees to reduce contact resistance between semiconductors and metal electrodes and for this reason, it is difficult to produce flexible transistors in use of plastic substrate. In order to solve this problem, the joint research team developed a technology that uses high frequency laser to selectively provide heat treatment to the metal electrodes of the molybden disulphide transistors that were made on a plastic substrate.

In the existing heat treatment process, heat in hundreds of degrees is applied to the entire area of the transistor, thus, it is impossible to use a plastic substrate that is weak against high temperature. On the other hand, the technology developed by the joint research team uses high frequency laser to selectively apply heat to the electrodes; thus, heat is rarely transferred to the plastic substrate. Such outcome implies the extensive application potential of molybden disulphide as a replacement of silicon in the field of flexible display and solar cell.

The first authors of this thesis are Professor Ung Choi of School of Advanced Materials Engineering in Kookmin University and Hyeok-jun Gwon in the doctorate course of Mechanical Engineering in the University of California, Berkeley, and this research was executed with the support of the National Research Foundation of Korea, Korea Evaluation Institute of Industrial Technology, and Air Force Office of Scientific Research.

Nano Research is a monthly academic journal that is jointly published by the Springer Publishing Company in Germany and Tsinghua University Publisher in China, and it is one of prestigious journals in the field of nanotechnology (quoted 6,963 times in 2013).