While a fascinating field, nanoscience does have its limitations. Scientists can make and manipulate nanoscale objects with greater precision, but the imagery for examining these objects is black-and-white. Until recently, scientists have not comprehended atomic-microscopy equivalent to color and how nanoscale chemistry reacts with light.
However, a new microscopy tool from the Department of Energy (DOE) Lawrence Berkeley National Laboratory (Berkeley Lab) provides high resolution chemical details previously unthinkable. The tool was born of a desire to investigate basic level solar-to-electric energy conversion.
The researchers discovered a way to combine scan/probe microscopy with optical spectroscopy and can evaluate chemical and optical processes on the nanoscale at the exact location they are happening.
Berkeley researchers have exceeded former limitations by designing a near-field probe they call the campanile, named after the UC Berkeley clock tower. The tiny probe has a four-sided tip and is fabricated on the end of an optical fiber. The 3D taper allows the device to channel light of all wavelengths down to an enhanced field at the tip. Gap size determines the resolution.
The Berkeley team is able to study indium-phosphide nanowires with the campanile. These nanowires are ideal to convert solar energy to electricity and can alter how sunlight is converted to electricity. This has never before been measured.
The upshot: Researchers want to understand the minutiae of indium-phosphide nanowires in order to more adeptly use them in photocatalysis or photovoltaic material. The construction and surface treatment influences charge recombination velocities, which, in turn, affects how efficiently a solar device can convert photons into usable electrons.