Molecular Self-Assembled Monolayers and Multilayers for Organic and Unconventional Inorganic Thin-Film Transistor Applications

• Published in: Advanced materials (Weinheim) Vol. 21; no. 14-15; pp. 1407 - 1433
• Main Authors: DiBenedetto, Sara A., Facchetti, Antonio, Ratner, Mark A., Marks, Tobin J.
• Format: Journal Article
• Language: English
• Published: Weinheim WILEY-VCH Verlag 20-04-2009; WILEY‐VCH Verlag
• Subjects: carbon nanotubes; high-k dielectrics; self-assembled monolayers; thin films; transistors
• ISSN: 0935-9648; 1521-4095
• DOI: 10.1002/adma.200803267

Principal goals in organic thin‐film transistor (OTFT) gate dielectric research include achieving: (i) low gate leakage currents and good chemical/thermal stability, (ii) minimized interface trap state densities to maximize charge transport efficiency, (iii) compatibility with both p‐ and n‐ channel organic semiconductors, (iv) enhanced capacitance to lower OTFT operating voltages, and (v) efficient fabrication via solution‐phase processing methods. In this Review, we focus on a prominent class of alternative gate dielectric materials: self‐assembled monolayers (SAMs) and multilayers (SAMTs) of organic molecules having good insulating properties and large capacitance values, requisite properties for addressing these challenges. We first describe the formation and properties of SAMs on various surfaces (metals and oxides), followed by a discussion of fundamental factors governing charge transport through SAMs. The last section focuses on the roles that SAMs and SAMTs play in OTFTs, such as surface treatments, gate dielectrics, and finally as the semiconductor layer in ultra‐thin OTFTs.
The progress of self‐assembled monolayers (SAM) and nanodielectrics in improving organic and inorganic TFT performance is described in this paper. The fundamentals of SAM fabrication, and their electrical properties in basic two terminal devices (see figure) has enabled rapid progress in the fabrication of low voltage organic and inorganic TFTs, logic circuits, and ultra thin SAM‐based TFTs