Numerical analysis of optical phase modulator operating at 2 μm wavelength using graphene/III-V hybrid metal-oxide-semiconductor capacitor

We propose an optical phase modulator with a hybrid metal-oxide-semiconductor (MOS) capacitor, consisting of single-layer graphene and III-V semiconductor waveguide. The proposed modulator is numerically analyzed in conjunction with the surface conductivity model of graphene. Since the absorption of graphene at a 2 µm wavelength can be suppressed by modulating the chemical potential of graphene with the practical gate bias, the phase modulation efficiency is predicted to be 0.051 V·cm with a total insertion loss of 0.85 dB when an n-InGaAs waveguide is used, showing the feasibility of the low-loss, high-efficiency graphene/III-V hybrid MOS optical phase modulator, which is useful in the future 2-µm optical fiber communication band.

Synthesis of p-n Heterojunctions via Aerosol Assisted Chemical Vapor Deposition to Enhance the Gas Sensing Properties of Tungsten Trioxide Nanowires: A Mini-Review

Here we discuss the aerosol-assisted synthesis of p–n heterojunction metal oxides and we report their gas sensing properties via a short review of the latest results achieved. In particular, we show that the decoration of one-dimensional tungsten oxide (n-type) with nanoparticles of different p-type oxides from transition metals such as Ni, Co or Ir enables achieving a chemical and electronic sensitization of the resulting hybrid metal oxide materials. This leads to remarkable differences in responsiveness to gases, showing that, to some extent, a selective detection of some major pollutant gases (NO2, H2S or NH3) would be possible. Results are critically reviewed, shortcomings are identified and future research directions are given.

Rational manufacture of yolk–shell and core–shell metal oxide double layers from silica-templated coordination polymer double layers

Yolk–shell and core–shell hybrid metal oxide double layers with varied metal compositions are rationally constructed via simple calcination of silica-templated coordination polymer double layers.