This thesis presents the fabrication and characterization of organic eld eecttransistors (OFETs) for sensor applications using polymeric semiconductor of poly (3-hexyl thiophene)(P3HT). Utilizing deionized (DI) water as gate insulator, operationvoltages of polymer eld eect transistors (polymer FETs) are reduced below 1V. Toease the microuidic channel integration of polymer FETs, a novel structure calledplanar OFET is designed and introduced. Comparing the output characteristics ofplanar OFET with the one of top-gate, bottom-contact OFET using gate probe instead of deposited gate electrode, it is shown that this planar OFET topology operatessuccessfully as eld eect transistor providing on-o ratio of about 50. It is statedthat P3HT lm deposition by spin-coating method leads higher on-o ratios thandrop-casting method for top-gate, bottom-contact OFET topology. Then, durabilityof P3HT to microfabrication processes is examined. In addition, sensitivity of P3HTto NaCl and KCl solutions is searched. Finally, microuidic channel encapsulation ofplanar polymer FETs with three dierent materials, polyvinyl alcohol (PVA), paryleneand polydimethylsiloxane (PDMS) is searched. PVA microuidic channels providingliquid ow are successfully formed. On-o ratios of 4 and 10 are obtained with planarpolymer FETs integrated into parylene and PDMS microuidic channels, respectively.

Bu tez polimer yariletken olarak poli (3-hekzil tiyofen)(P3HT) kullanan organikalan etkili transistorlerin (OFET) sensor uygulamalar icin fabrikasyon ve karakterizasyonunusunmaktadr. Kap yaltkan olarak deiyonize (DI) sudan yararlanlarak,polimer alan etkili transistorlerin (polimer FET'ler) calsma voltajlar 1 V'un altnadusurulmustur. Polimer FET'lerin mikroakskan kanala tumlestirilmesini kolaylastrmakicin, yeni bir duzlemsel OFET yaps tasarlanms ve tantlmstr. Bu duzlemsel OFET'incks karakteristigi ust-kap alt-kontak bir OFET'inki ile karslastrldgnda, duzlemselOFET'in yaklask 50 acma-kapama oran saglayarak, alan etkili transistor olarak basarile calstg gosterilmistir. Ust-kap, alt-kontakt OFET yaps icin, doner-kaplamayontemi ile P3HT lmi depolamann damla-kaplama yontemine gore daha yuksekacma-kapama oranna yol actg belirtilmistir. Daha sonra, P3HT'nin mikrofabrikasyonislemlerine dayankllg incelenmistir. Ayrca, P3HT'nin NaCl ve KCl cozeltilerine duyarllg arastrlmstr. Son olarak, polimer alan etkili transistorlerin uc farkl malzemeile, polivinil alkol (PVA), parylene ve polidimetilsiloksan (PDMS), mikroakskan kanallarile kapsullenmesi arastrlmstr. Sv aks saglayan PVA mikroakskan kanallarbasaryla olusturulmustur. Srasyla, acma ve kapama oranlar 4 ve 10 olan duzlemselpolimer FET'ler parylene ve PDMS mikroakskan kanallarna tumlestirilmistir.