Paul Newhouse

High electron mobility W-doped In2O3 thin films by pulsed laser deposition

High electron mobility thin films of In2−xWxO3+y(0⩽x⩽0.075) were prepared on amorphous SiO2 and single-crystal yttria-stablized zirconia (001) substrates by pulsed laser deposition. Mobilities ranged between 66 and 112cm2∕Vs depending on the substrate type and deposition conditions, and the highest mobility was observed at a W-dopant concentration of x∼0.03. A small band gap shift was detected from films with increasing electron carrier density; the electron effective mass calculated from Burstein-Moss theory was 0.3me. In2−xWxO3+y films have high visible transmittance of ∼80%.

Colorimetric Screening for High-Throughput Discovery of Light Absorbers

High-throughput screening is a powerful approach for identifying new functional materials in unexplored material spaces. With library synthesis capable of producing 10(5) to 10(6) samples per day, methods for material screening at rates greater than 1 Hz must be developed. For the discovery of new solar light absorbers, this throughput cannot be attained using standard instrumentation. Screening certain properties, such as the bandgap, are of interest only for phase pure materials, which comprise a small fraction of the samples in a typical solid-state material library. We demonstrate the utility of colorimetric screening based on processing photoscanned images of combinatorial libraries to quickly identify distinct phase regions, isolate samples with desired bandgap, and qualitatively identify samples that are suitable for complementary measurements. Using multiple quaternary oxide libraries containing thousands of materials, we compare colorimetric screening and UV-vis spectroscopy results, demonstrating successful identification of compounds with bandgap suitable for solar applications.