MICRA Project Descriptions: Summer 2006
1.
Beam Induced Deposition of Contacts to Nanofibers
Prof. John Melngailis (EE,
UMCP) and Dr. Matthew Ervin (ARL)
The investigation of direct-write electron beam induced deposition processes for nanoscale contact formation, critical to the development of nanoscale electronic circuits and novel sensor technologies, is being conducted in joint efforts between UMD and ARL. In this research, novel gas-phase metal precursors are used in a high-vacuum environment to form local metal contacts to nanoscale active elements to create viable electronic devices. Carbon nanotubes, conducting polymer nanofibers, and inorganic semiconducting nanowires are being investigated for high speed field-effect transistors and sensitive detectors. The experimental efforts envisioned within this research project include the assembly of a gas injection system, cleanroom processing of test wafers, and investigations of parameters affecting the deposition rate (e.g., electron current density, electron dose, substrate temperature, etc.) and the resultant metal contact quality. Physical characterization of the metal contacts using nano- and microprobe I/V techniques, scanning electron microscopy, and atomic force microscopy is envisioned.
2.
Efficient Generation of Terahertz Pulses from InN via Optical Pumping
Prof. T. Murphy (EE,
UMCP), Dr. Michael Wraback (ARL), and Dr. H. Shen (ARL)
The goal of this program is to investigate new materials that could be used for generating and detecting radiation in the terahertz (THz) region of the electromagnetic spectrum. The terahertz region is a relatively unexplored part of the electromagnetic spectrum between electronic (100 GHz) and optical frequencies (10 THz). Most dry, non-metallic materials are transparent to THz signals, but unlike x-rays, THz radiation is harmless and non-ionizing. For this reason, THz radiation is seen as a promising alternative for imaging, chemical identificaion and medical diagnostics. Students working on this project will help to investigate THz generation from InN, a new material that could potentially enable more compact and efficient THz sources.
3.
Integration and Characterization of Functional Nano-Technology Materials on a Single Chip
Prof. R. D. Vispute (Physics,
UMCP) and Dr. Stephen Kilpatrick (ARL)
New materials demonstrating feasibility for the integration of nanodimensional devices with multifunctional characteristics on a single platform are being developed for application to advanced electronics and sensors of extremely small size operating with low power requirements. This research project, based on joint efforts between UMD and ARL, investigates processes for surface selective patterning, masking, and atomic scale engineering for the growth of CNTs which can act as electronic devices, interconnects, or as a thermal management material. It also focuses on the integration and characterization of nanomaterials including GaN/AlN nanowires, ZnO nanowires/nanorods, and metallic nanowires (Ag, Au, Pt) with potential applications that include electrical, optical, mechanical, and active sensing modes. The MERIT student will work jointly with UMD and ARL researchers to investigate the growth and characterization of nucleation layers and heterostructures for the control of nanostructured materials, with the vision toward developing techniques for the integration of multifunctional nanoscale devices. The nanowires/nanorods will be grown at UMD, while the CNTs will be grown at ARL. Physical characterization of nanostructures using Rutherford backscattering, scanning electron microscopy, and atomic force microscopy is envisioned.
4.
Modeling and Measurement of Semiconducting Nanotube Transistors for Sensing Applications
Prof. Michael S. Fuhrer (Physics, UMCP)
and Dr. Barbara Nichols (ARL)
Research on the growth and characterization of carbon nanotube (CNT) based electronic devices is being conducted as part of the development of nanoscale electronic circuits and novel sensor technologies for ultraminiaturized, low power chemical/biological sensing applications. In particular, semiconducting single-wall carbon nanotubes, grown at both UMD and ARL, are being investigated for high speed field-effect transistors and chemical gas sensors. Nanoscale electronic test architectures are in development for fabrication in ARL’s Class 10/100 cleanroom facility, using in-house electron beam lithography and other nanofabrication capabilities. This research project, based on joint efforts between UMD and ARL, will investigate the fundamental transport properties of carbon nanotube based electronic structures and devices. Experimental efforts include the catalyzed growth of SW-CNTs, nanoscale device fabrication, I/V and C/V investigation of electron/hole transport in the nanoelectronic structures as a function of temperature and ambient environment, and physical characterization of nanostructures using scanning electron microscopy and atomic force microscopy. The design of electronic circuits integrating nanoscale active components is within the scope of this research.
5.
Modeling and Measurement of Semiconducting Nanotube Transistors for Sensing Applications
Prof. Neil Goldsman (EE, UMCP) and Dr. Alma Wickenden (ARL)
The modeling and theoretical characterization of electronic properties and charge transport in carbon nanotubes (CNT) are being investigated as part of the development of nanoscale electronic circuits for unique applications, including terahertz communication and novel sensor technologies. In the theoretical foundation of the proposed research, Monte Carlo (MC) simulators have been developed that provide insight into key transport parameters in CNTs, including electron drift velocity and field-dependent mobility. Our research also predicts certain novel CNT behavior characteristics, including velocity overshoot, and velocity oscillations that depend on CNT diameter and length. We have also developed theoretical models which describe the interfaces between CNTs and other materials, and have combined our CNT MC results and our experience in the modeling of nanoscale devices to yield a methodology for modeling CNT based field-effect transistors (FETs). In this research project, modeling of the charge transport in actual CNT devices will be explored. In particular, this research will attempt to correlate models and experimental data to understand how adsorbates, contact and dielectric interfaces, and charge traps contribute to scattering within carbon nanotubes, and how adsorbate sensitivity and selectivity can be maximized. The development of computer graphics and visual displays of data and results will be an integral part of this research project.