Isolate Utilization of Plasmonic Hot Holes in Optoelectronic Enhancement for Copper Iodide (CuI): A Cross-Investigation by Confocal Kelvin Probe Force Microscopy

摘要

Nonradiative decays of surface plasmon (SP) can generate photocarriers infemtosecond, and it therefore has been attracting widespread researchattention in ultrafast optoelectronics. Taking advantage of the probetechnique, Kelvin probe force microscopy (KPFM) can characterize the spatialdistribution of hot carriers in nanoscale and thereby provide necessaryanalysis for device investigation and engineering. In this work, the behavior ofplasmonic hot holes is demonstrated for Ag nanoparticles (NPs) based on thefabrication of CuI hole transport layers. The morphological, optical, andelectronic properties of Ag NPs and CuI films are systematically investigated.With the confocal lasers of over- and sub-bandgap wavelength, reversedevolution trends of surface potentials are observed by KPFM, indicating theeffective injection of hot holes into CuI valence band (VB). Cross-verification isalso performed based on the fabrication of metal–semiconductor–metal(MSM) photodetectors, and the photoelectrical tests highly dovetail with thesurface potential evolution. This research provides an important reference forthe plasmonic photoelectronics in both device design and research methods.