Fabrication of p-Ni0.8Cu0.2WO4/n-Si heterojunction diode and 1 MHz rectifier operation

Abstract

Authors report the fabrication of heterostructure diode adopting p-Ni_0.8Cu_0.2WO₄ oxide/n-Si junction, and its demonstration toward high speed rectifier circuit upto 1 MHz. Newly developed p-type Cu-doped NiWO₄ was synthesized by solid-state reaction, and its thin-film form was successfully deposited by e-beam evaporation method. From X-ray diffraction and Raman spectroscopy, it is confirmed that all the deposited Cu-doped NiWO₄ films showed amorphous phases independent from substrate heating temperature. UV-visible transmittance and electrical resistivity value decreases, as increasing substrate heating temperature from 100 to 300 ^oC, revealing that optical transparency and electrical conductivity were in the trade-off relation in Cu-doped NiWO₄ film. By fabricating p-Ni_0.8Cu_0.2WO₄/n-Si heterostructure diodes, a highly rectifying behaviour can be attained with an ideality factor and an on/off current ratio of 1.23 and ~10⁴, respectively. When we configure the AC to DC converting half-wave rectifier circuit with p-Ni_0.8Cu_0.2WO₄/n-Si diode, a high-speed operation upto 1 MHz was demonstrated, as strongly supporting that our newly developed p-type oxide can be utilized as a key component in practical oxide-based electronics such as radio frequency identification.