Lead Zirconium Titanate Films and Devices Made by a Low- Temperature Solution-Based Process

As the most important multifunctional oxide material, lead zirconium titanate (PZT) has a diverse range of applications such as piezo actuators, ferroelectric nonvolatile memories, sensors, and transducers due to its excellent structural and electrical properties. However, it generally requires a high annealing temperature (above 600°C) to attain the desired properties, which hinders the integration of PZT with silicon-based Complementary Metal Oxide Semiconductor (CMOS). Therefore, the fabrication of PZT films by a chemical solution deposition (CSD) at temperatures compatible with Si-CMOS technology or even with polymeric substrate for flexible electronics would be of high technological interest. So far, different strategies to decrease the crystallization temperature of CSD-derived PZT films have been studied. This chapter presents a critical review on the low-temperature solution-processed PZT films and devices, and addresses challenges for fundamental understanding and practical integration of multifunctional PZT in devices. In the first part, recent advances in fabrication of CSD-derived PZT films at a low temperature are thoroughly reviewed. The second part discusses various techniques for patterning PZT into micro-nano-sized patterns. Lastly, some potential applications of the low-temperature CSD-derived PZT films and devices are demonstrated

Peptide aptamer-modified single-walled carbon nanotube-based transistors for high-performance biosensors

Biosensors employing single-walled carbon nanotube field-effect transistors (SWCNT FETs) offer ultimate sensitivity. However, besides the sensitivity, a high selectivity is critically important to distinguish the true signal from interference signals in a non-controlled environment. This work presents the first demonstration of the successful integration of a novel peptide aptamer with a liquid-gated SWCNT FET to achieve highly sensitive and specific detection of Cathepsin E (CatE), a useful prognostic biomarker for cancer diagnosis. Novel peptide aptamers that specifically recognize CatE are engineered by systemic in vitro evolution. The SWCNTs were firstly grown using the thermal chemical vapor deposition (CVD) method and then were employed as a channel to fabricate a SWCNT FET device. Next, the SWCNTs were functionalized by noncovalent immobilization of the peptide aptamer using 1-pyrenebutanoic acid succinimidyl ester (PBASE) linker. The resulting FET sensors exhibited a high selectivity (no response to bovine serum albumin and cathepsin K) and label-free detection of CatE at unprecedentedly low concentrations in both phosphate-buffered saline (2.3 pM) and human serum (0.23 nM). Our results highlight the use of peptide aptamer-modified SWCNT FET sensors as a promising platform for near-patient testing and point-of-care testing applications