Nanotechnology can enable a new generation of sensor systems due to the potentially unique and advantageous properties of these materials. In particular, the properties of nanostructures such as nanowires, nanofibers, nanorods, and nanoribbons are now being investigated to enable new sensing material properties and approaches. In order to achieve the potential of nanotechnology, basic and fundamental capabilities are needed in order to produce and evaluate sensor systems based on these materials. These include the ability to reproducibly fabricate sensors, understand the material properties, and determine their sensing mechanisms. However, the

very nature of these materials makes the use of traditional sensor fabrication and characterization techniques, such as those used for microsystems, problematic. This chapter describes the challenges associated with the reproducible fabrication of nanostructures into microsensor systems; characterization of the basic properties of a nanowire; and investigations into the sensing mechanism of nanostructures of different crystal structure. These examples suggest that the transition from microsystem technology into those based on nanostructures involve a series of basic challenges beyond that seen in macroscopic materials. However, if these challenges can be met, the advent of nanotechnology into sensor systems enables the possibility of new sensor systems significantly changing how measurements are done. New sensor systems that can be enabled by nanotechnology, such as “Lick and Stick” smart sensor systems, are discussed. 2.1 Overview of Challenges in Nanosensor

TechnologySensor technology allows measurement of a range of parameters within operational systems to provide more complete information on the environment, system operational parameters, or human health. Sensor technology can have impact on a vast range of human activities, including safety, security, medicine, industrial process control, systems operation, and situational awareness in general [1]. This includes the use of nanomaterials for sensors in aerospace applications, which is addressed in another chapter in this book [2]. A significant motivation behind the development and use of nanotechnology in sensor development is that its inherent advantages can potentially enable a paradigm shift in the capabilities afforded by sensor technology and related systems. The vision is that not only can nanotechnology provide comparable capabilities as traditional technologies and even microsystems, but it will enable a revolution in sensor technology and correspondingly have a significant effect on the average person’s health and lifestyle [1-3].In order to achieve such a revolution, nanotechnology must be able to provide capabilities at least comparable, if not superior, to that of conventional sensor systems. Some of the major enabling technical areas for nanotechnology to surpass conventional sensor systems

include sensor fabrication reproducibility; significantly reduced power consumption; improved sensor selectivity, sensitivity, and reliability; ease of application and integration; improved redundancy and cross-correlation; and multiparameter, orthogonal detection [4-6]. These technical challenges are consistent with what is necessary regardless of whether the sensor is based on nanotechnology or other approaches; they address basic operational parameters for a sensor system. In the end, a user typically does not care that a sensor system is based on nanotechnology; they first care that the sensor system meets the needs of the application. However, a major technical hurdle associated with achieving the vision of nanotechnology for sensor systems is the ability to produce operational sensors for the targeted application based on these materials.