Author(s):
Krayer, Lisa J. ; Palm, Kevin J. ; Gong, Chen [UNESP] ; Torres, Alberto ; Villegas, Cesar E. P. [UNESP] ; Rocha, Alexandre R. ; Leite, Marina S. ; Munday, Jeremy N.
Date: 2020
Persistent ID: http://hdl.handle.net/11449/200884
Origin: Oasisbr
Subject(s): electron attenuation length; hot carriers; metal alloys; near-infrared absorption; photodetection; Schottky photodiodes; electron attenuation length; electron attenuation length; hot carriers; hot carriers; metal alloys; metal alloys; near-infrared absorption; near-infrared absorption; photodetection; photodetection; Schottky photodiodes; Schottky photodiodes
Description
Made available in DSpace on 2020-12-12T02:18:40Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-07-15
Alloying of metals provides a vast parameter space for tuning of material, chemical, and mechanical properties, impacting disciplines ranging from photonics and catalysis to aerospace. From an optical point-of-view, pure thin metal films yield enhanced light absorption due to their cavity effects. However, an ideal metal-semiconductor photodetector requires not only high absorption, but also long hot carrier attenuation lengths in order to efficiently collect excited carriers. Here we demonstrate that Ag-Au alloys provide an ideal model system for controlling the optical and electrical responses in nanoscale thin metal films for hot carrier photodetectors with improved performance. While pure Ag and Au have long hot carrier attenuation lengths >20 nm, their optical absorption is insufficient for high efficiency devices. Instead, we find that alloying Ag and Au enhances the absorption by -50% while maintaining attenuation lengths >15 nm, currently limited by grain boundary scattering, although the electron attenuation length of pure Au outperforms pure Ag as well as all of the alloys investigated here. Further, our density functional theory analysis shows that the addition of small amounts of Au to the Ag lattice significantly enhances the hot hole generation rate. Combined, these findings suggest a route to high efficiency hot carrier devices based on metallic alloying with potential applications ranging from photodetectors and sensors to improved catalytic materials.
Department of Electrical and Computer Engineering Institute for Research in Electronics and Applied Physics Department of Physics Department of Materials Science and Engineering University of Maryland
Instituto de Física Teórica Saõ Paulo State University (UNESP)
Departamento de Ciências Universidad Privada Del Norte
Department of Material Science and Engineering Department of Electrical and Computer Engineering University of California
Instituto de Física Teórica Saõ Paulo State University (UNESP)
