NNN Researchers Collaborate on Thermal Characterization Technique for Nanoscale Devices

National Nanomanufacturing Network: The Nano Engineering Lab at the University of California-Berkeley is the faculty research laboratory of Prof. Arunava Majumdar of the Center for Scalable and Integrated Nanomanufacturing (SINAM). The lab is comprised of a range of multi-disciplinary researchers studying a variety of nanotructured materials for applications in thermoelectricity, solar conversion, enhanced phase change heat transfer, and chemical  and biological sensing.

In order to study thermal transport in low-dimensional materials, along with materials and devices for thermoelectric energy conversion, new instruments and techniques are required which can be used to identify the thermal conductivities of thin films, nanostructured materials, and solids. During the summer of 2008, Janice Hudgings, Associate Professor and Physics Department Chair at Mount Holyoke College, was a visiting researcher at the Nano Engineering Lab at UC-Berkeley/SINAM.

Prof. Hudgings, a member of the Center for Hierarchical Manufacturing (CHM) at the University of Massachusetts at Amherst, leads a group at Mount Holyoke College that studies the device physics of a range of semiconductor devices, including semiconductor lasers, amplifiers, and solar cells. The techniques developed by her group use spatially resolved thermal mapping on the nanoscale to probe the internal physics of working optoelectronic devices, quantifying gain and absorption parameters as well as identifying effects such as gain saturation and facet heating in lasers, absorbers, and semiconductor optical amplifiers. This research has resulted in a new characterization tool for nanomanufacturing systems in which large area materials characterization must be done with nanoscale resolution.

During her visit this past summer, Hudgings worked with researchers in the Nano Engineering Lab to develop a non-contact thermal characterization technique based on thermoreflectance, which can be used to identify the thermal conductivities of thin films, nanostructured materials, and solids. In this research collaboration, Hudgings’ expertise in fiber optics and 3D thermography was critical to the success of the team. A paper describing the technique, fiber aligned 
thermal interrogation or FATI, is in preparation for the Review of Scientific Instruments. The Nano Engineering Lab at SINAM will be utilizing the technique to investigate the thermal properties of nanostructured thermoelectric materials, thermal interface materials, and thermal insulating materials. This complimentary collaboration successfully engaged expertise from separate NSF Nanoscale Science and Engineering Centers in order to provide an advanced capability.