Useful information must have the following characteristics: a) integral, i.e. as many different type of stimuli as possible, b) acquired in close physical proximity, c) preprocessed and d) transmitted to a remote location for further more sophisticated processing. In order to acquire information which is useful for military applications, sensors must have the following additional requirements; increased packing density, enhanced sensitivity, radiation hardness, high speed, small dissipation, integration, remote programming, tribology, corrosion, stealth and reduced cost. This is a formidable task which requires the collaboration of scientists from the different disciplines of physics, chemistry, materials science, and engineering. Moreover in order to ground these studies in reality, contributions by the consumers (i.e. military users) are crucial.

Fig. 1 Conceptual Design of Integrated Nanostructured Supersensors.

We envision that this MURI will be a first step toward the development of a supersensor that is sensitive to different types of stimuli (magnetic, optical, chemical and biological), will allow local limited preprocessing and decision making and will transmit this data to a remote location. The MURI will address some of the key issues related to this formidable task including; developing, miniaturizing and improving the sensitivity of different nanosensors and integrating them into a single chip together with power supplies and data processing devices. A number of basic research issues arise on the road toward this goal and will be addressed here. These include controlling interfaces between dissimilar materials, improving the sensitivity of individual sensors, transfer and wafer bonding of dissimilar sensors and materials, and subjecting different sensors to a variety of environments. In addition to the development of individual sensors, this proposal will stress the integration of these into a single device. Because of the optimization of different sensors requires radically different conditions (substrates, growth methods, temperature,…), integration will be performed by slicing and moving them (once they are prepared) to the final chip. We envision that there will be a number of issues of compatibility, electrical, chemical and physical interaction, programming, etc issues which will have to be addressed as they arise. The development of an integral nanosensor would also have many nonmilitary applications in disparate fields such as process monitoring, environmental, robotics, and probably others not yet envisioned.

To make this task a success, we have assembled a lean group that consists of experts with proven records in integration, magnetic, infrared, chemical and biological sensors, and miniaturization. The participants are chemistry, physics, and engineering faculty members from UCSD together with researchers from the Air Force Research Laboratory at Wright-Patterson Air Force Base (AFRL-WPAFB) and the U.S. Army Soldier and Biochemical Command (SBCCOM) Laboratories. It is crucial to realize that in addition to solving several specific research problems, this MURI will fulfill an important educational objective: namely to educate young investigators in this field. This will be done by intimately involving graduate students and postdocs in the research problems to be addressed. In addition, we will have graduate students and postdocs specifically assigned to work at the partner Defense labs. They will become familiar with state of the art facilities available there and with the specific needs the end users have. In order to assure that proper progress is made, an external advisory committee will be named to evaluate and advise the MURI director.

Statement of the Problem

In order to focus the problem, it is crucial to specify the final aim more precisely. We envision that the integral supersensor to be developed under this proposal will be aimed toward detecting a massive moving object which emits infrared radiation and produces a variety of chemical and biological outputs. Since it is impossible to have all sensors operational all the time, a logical hierarchy will be developed to trigger one sensor based on the response from others. To conserve power and decrease cost, nanostructuring and overall integration on a single chip will be investigated. We expect that in the future these types of sensors will be self-powered, miniaturized and massively deployable. More specifically, we will aim toward integrating all sensors on Si substrates, although this aim may have to be revised depending on the results obtained during the initial stages of research.