UV Photodetectors With Thin-Film Si Nanoparticle Active Medium

Abstract

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.