Nanosecond and Nanometer Exploration Bryan D. Huey , University of Connecticut, DMR 0909091

1. Materials World Network-- Ultrafast Switching of Phase Change Materials: Combined Nanosecond and Nanometer ExplorationBryan D. Huey, University of Connecticut, DMR 0909091 • Impact: Phase change materials (PCM’s) are an important candidate for future data storage systems due to their fast switching speeds, high reliability, and potential for low power operation. • Explanation: Google data centers use 0.01% of global electricity, and by 2020 are projected to essentially require their own coal-burning power plant to operate. Shifting to solid state memory from spinning magnetic hard drives is an obvious area for improvement. Performance benefits of solid-state PCM’s for storage class memory, rugged computing, and mobile applications are also abundant. However, the switching mechanism between distinct amorphous and crystalline data states is still not well understood in these materials. In-situ microscopy is therefore promising for evaluating switching dynamics ultimately to optimize device performance.

2. Nanosecond and Nanometer ExplorationBryan D. Huey, University of Connecticut, DMR 0909091 • In collaboration with international project partners from Lancaster University, including IljaGrishin (PhD exchange student) • Amorphous and crystalline data-bits investigated: • Amorphous bits in crystalline GST: 75-120 picoJoulesin 30 picoseconds (pulsed Nd:YAG 532 nm laser). • Crystalline bits in amorphous GT: 200 nanoJoulesin 200 microseconds (continuous Ar blue laser). • Structural change with temperature: • Subtle change in topography due to local change in density of distinct phases, correlated with change of index of refraction. • Current mapping feasible, though challenging in air (vacuum measurements planned for future). • Pre-switched devices acquired from partners in Korea (KAIST) for cross-sectioning and analysis. • In-situ variable temperature measurements now possible. Topographic AFM images of amorphous bits in a crystalline GST film. Bits written using various powers as labeled, with tracks separated by 10 um (y) on a 5 um pitch (x). 75 pJ 90 pJ 105 pJ 120 pJ 5um

3. Advances in Nanoscale MeasurementsBryan D. Huey, University of Connecticut, DMR 0909091 PI Huey and international partner Kolosov co-organized a symposium at the Materials Research Society Annual Meeting (Fall 2010). ‘Novel Development and Applications in Scanning Probe Microscopy” ran for 4 full days with 100 presentations. The audience included industry, faculty, graduate students, undergraduate students, and several high school students as well. Uniquely, this symposium included a 2 hour panel discussion on future directions for SPM. Panelists included academic, industrial, government, and funding agency scientists from around the world. The discussion particularly challenged developers to improve future nanoscale measurement capabilities in terms of speed, chemical specificity, and ease of use. AFM image of ~300x300x60 nm tin oxide nanostructures, looking remarkably similar to marshmallows in hot chocolate (image featured in demonstrations to high school students and teachers during summer 2011).