A dye sensitized TiO2 photodetector has been integrated with a DNA detection method based on non-cross-linking hybridization of DNA-functionalized gold nanoparticles, resulting in a disposable colorimetric biosensor. We present a new approach for the fabrication of dye sensitized TiO2 photodetectors by an inkjet printing technique-a non-contact digital, additive, no mask and no vacuum patterning method, ideal for cost efficient mass production. The developed biosensor was compared against a dye sensitized photodetector fabricated by the traditional "doctor blade" method. Detection of gold nanoparticle aggregation was possible for concentrations as low as 1.0 nM for the "doctor blade" system, and 1.5 nM for the inkjet printed photodetector. The demonstrated sensitivity limits of developed biosensors are comparable to those of spectrophotometric techniques (1.0 nM). Our results show that a difference higher than 17% by traditional photodetector and 6% by inkjet printed in the photoresponses for the complementary and non-complementary gold nanoprobe assays could be attained for a specific DNA sequence from Mycobacterium tuberculosis, the etiologic agent of human tuberculosis. The decrease of costs associated with molecular diagnostic provided by a platform such as the one presented here may prove of paramount importance in developing countries. © 2009 Elsevier B.V. All rights reserved.

This paper discusses the properties of sputtered multicomponent amorphous dielectrics based on mixtures of high-κ and high-bandgap materials and their integration in oxide TFTs, with processing temperatures not exceeding 1 50° C. Even if Ta2O5 films are already amorphous, multicomponent materials such as Ta2O5-SiO2 and Ta2O5-Al2O3 allow an increase in the bandgap and the smoothness of the films, reducing their leakage current and improving (in the case of Ta2O5-SiO2)the dielectric/semiconductor interface properties when these dielectrics are integrated in TFTs. For HfO2- based dielectrics, the advantages of multicomponent materials are even clearer: while HfO2 films present a polycrystalline structure and a rough surface, HfO2-SiO2 films exhibit an amorphous structure and a very smooth surface. The integration of the multicomponent dielectrics in GIZO TFTs allows remarkable performance, comparable with that of GIZO TFTs using SiO2 deposited at 400°C by PECVD. For instance, with Ta2O5-SiO2 as the dielectric layer, field-effect mobility of 35 cm2/(V-sec), close to 0 V turn-on voltage, an on/off ratio higher than 106, a subthreshold slope of 0.24 V/dec, and a small/recoverable threshold voltage shifts under constant current (ID = 10 μ,A) stress during 24 hours are achieved. Initial results with multilayers of SiO2/HfO 2-SiO2/SiO2 are also shown, allowing a lower leakage current with lower thickness and excellent device performance. © Copyright 2010 Society for Information Display.

Long-term electrical stability measurements, including current/bias stress and aging over 18 months of idle shelf life are presented for GIZO-based TFTs. The effects of oxygen partial pressure, annealing temperature and passivation are discussed. Optimized devices show highly stable properties, such as a recoverable ΔVT<0.5 V after 24h of 1D=10 μA stress, quite promising for integration in electronic circuits.

Long-term electrical stability measurements, including current/bias stress and aging over 18 months of idle shelf life are presented for GIZO-based TFTs. The effects of oxygen partial pressure, annealing temperature and passivation are discussed. Optimized devices show highly stable properties, such as a recoverable ΔV T<0.5 V after 24h of I D=10 μA stress, quite promising for integration in electronic circuits. © 2010 SID.