UV Photodetectors With Thin-Film Si Nanoparticle Active Medium

We constructed ultraviolet (UV) photodetectors using thin films of silicon nanoparticles as active media. The Si nanoparticle films are electrodeposited at room temperature on Si p-type substrates. Uniform silicon nanoparticles of 1-nm diameter are dispersed from Si wafers using electrochemical etching. The nanoparticles are ultrabright under UV excitation, with nanosecond luminescence time characteristics. Current-voltage (I--V) characteristics indicate a photoconductor in series with a diode-like junction with a large enhancement in the forward current under UV illumination. Our results point to a sensitive UV detector with good visible blindness where the particle films effectively constitutes a wide-bandgap material.