Thin Film Silicon Nanoparticle UV Photodetector

We constructed ultraviolet (UV) photodetectors by room-temperature deposition of Si nanoparticle films on Si p-type substrates. Silicon nanoparticles of 1-nm diameter are dispersed from Si wafers using electrochemical etching. The current-voltage characteristics indicate a photoconductor in series with a diode-like junction with a large enhancement in the forward current under UV illumination. With increasing wavelength, the response drops rapidly, dropping to a few percent at 560 nm. These results point to a sensitive UV detector with good visible blindness where the particle films effectively constitutes a wide-bandgap material.