Development of high performance organic devices by controlling charge carrier density

Organic field-effect transistor (OFETs), the central building blocks of organic electronics, still suffer from low performance and difficulty in manufacturing circuits. This is due in part to the absence of doping, which has mostly been excluded from OFET applications for the serious concern about uncontrollable dopant diffusion. Doping enabled modern semiconductor industry to build the essential components like ohmic contacts and P-N junctions empowering the composed devices to function as designed. Recent breakthroughs in organic semiconductors and organic doping techniques demonstrated that doping can be a key enabler for high-performance OFETs too. However, the present knowledge of organic doping mechanism, in particular the special doping roles, the doping principles and potentials for OFETs, is very limited. Therefore, in this presentation, I address OFET doping from a device perspective. The talk commences with a brief review of doping basics, followed by an overview of the doping roles in advanced silicon metal-oxide-semiconductor field-effect transistors. I also examine the achievements in OFET doping by separately dealing with channel, contact, and overall (channel + contact) doping to clarify the corresponding doping roles. In the end, the doping mechanisms, doping techniques, and dopants associated with OFET applications are reviewed.

In addition, I introduce a different approach to control charge carrier density by applying new high-k dielectrics based on solid state electrolyte based gate insulator (SEGI).