Correlation between dielectric/organic interface properties and key electrical parameters in PPV-based OFETs

Year: 2008

Authors: Todescato F., Capelli R., Dinelli F., Murgia M., Camaioni N., Yang M.J., Bozio R., Muccini M.

Autors Affiliation: Consiglio Nazionale delle Ricerche (CNR), Istituto per lo Studio dei Materiali Nanostrutturati (ISMN), Via P. Gobetti 101, I-40129 Bologna, Italy; Consiglio Nazionale delle Ricerche (CNR), Istituto per i Processi Chimico Fisici, Via Moruzzi, 1 I-56124 Pisa, Italy; Consiglio Nazionale delle Ricerche (CNR), Istituto per la sintesi organica e la Fotoreattivita` (ISOF), Via P. Gobetti 101, I-40129 Bologna, Italy; Department of Polymer Science and Engineering, Zhejiang UniVersity, Hangzhou 310027, China; Dipartimento di Scienze Chimiche, UniVersita` degli Studi di Padova, Via Marzolo, 1, I-35131 Padova, Italy

Abstract: We report on the influence of the dielectric/organic interface properties on the electrical characteristics of field-effect transistors based on polyphenylenevinylene derivatives. Through a systematic investigation of the most common dielectric surface treatments, a direct correlation of their effect on the field-effect electrical parameters, such as charge carrier mobility, On/Off current ratio, threshold voltage, and current hysteresis, has been established. It is found that the presence of OH groups at the dielectric surface, already known to act as carrier traps for electrons, decreases the hole mobility whereas it does not substantially affect the other electrical characteristics. The treatment of silicon dioxide surfaces with gas phase molecules such as octadecyltrichlorosilane and hexamethyldisilazane leads to an improvement in hole mobility as well as to a decrease in current hysteresis. The effects of a dielectric polymer layer spin coated onto silicon dioxide substrates before deposition of the semiconductor polymer can be related not only to the OH groups density but also to the interaction between the dielectric and the semiconductor molecules. Specifically, the elimination of the OH groups produces the same effect observed with hexamethyldisilazane. The hole mobility values obtained with hexamethyldisilazane and polymer dielectrics are the highest reported to date for PPV-based field-effect transistors.

Journal/Review: JOURNAL OF PHYSICAL CHEMISTRY B

Volume: 112 (33)      Pages from: 10130  to: 10136

More Information: This work was supported at Bologna by EU under Project No. FP6-IST-015034 (OLAS) and by Italian Ministry MIUR under Project Nos. FIRB – RBNE033KMA and FIRB – RBIP06JWBH (NODIS), and by Regione Emilia-Romagna under Project MISTER. Authors thank R. Zamboni for stimulating discussions.
KeyWords: FIELD-EFFECT TRANSISTORS; THIN-FILM TRANSISTORS; ORGANIC SEMICONDUCTORS; CHARGE-TRANSPORT; GATE INSULATORS; ELECTRONICS; THRESHOLD; SUBSTRATE; MOBILITY; BEHAVIOR
DOI: 10.1021/jp8012255

ImpactFactor: 4.189
Citations: 42
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