Photo-Thermoelectric Conversion of Plasmonic Nanohole Array

Plasmonic photo-thermoelectric conversion offers an alternative photodetection mechanism that is not restricted by semiconductor bandgaps. Here, we report a plasmonic photodetector consisting of an ultra-thin silver film with nanohole array, whose photodetection mechanism is based on thermoelectric conversion triggered by plasmonic local heating. The detector exhibits a maximum photocurrent at the wavelength of the surface plasmon polaritons, determined by the periodicity of the nanoholes. Hence, the response wavelength of the detector can be controlled via the morphological parameters of the nanohole pattern. The contribution of plasmonic local heating to thermoelectric conversion is verified experimentally and numerically, enabling discussion on the mechanisms governing light detection. These results provide a starting point for the development of other nanoscale photodetectors.

The Growth of Ga2O3 Nanowires on Silicon for Ultraviolet Photodetector

We investigated the effect of silver catalysts to enhance the growth of Ga2O3 nanowires. The growth of Ga2O3 nanowires on a P+-Si (100) substrate was demonstrated by using a thermal oxidation technique at high temperatures (~1000 °C) in the presence of a thin silver film that serves as a catalyst layer. We present the results of morphological, compositional, and electrical characterization of the Ga2O3 nanowires, including the measurements on photoconductance and transient time. Our results show that highly oriented, dense and long Ga2O3 nanowires can be grown directly on the surface of silicon. The Ga2O3 nanowires, with their inherent n-type characteristics formed a pn heterojunction when grown on silicon. The heterojunction showed rectifying characteristics and excellent UV photoresponse.