Microwave Dissipation Spectra in Arrays of Silicon Nanowires

The transmission and reflection scattering parameters of arrays of silicon nanowires (SiNWs) directly assembled onto co-planar waveguides (CPWs) have been measured from 0.1 to 50 GHz at room temperature. Typical arrays consisted of between 10³ to 10⁴ SiNWs aligned parallel to the electric field polarization of the propagating microwave field. Scattering parameters were measured on CPWs both before and after nanomaterial assembly. Highly reproducible CPW characteristics and careful use of control samples to quantify systematic reproducibility allowed clear separation of nanomaterial effects from the characteristics of the bare CPWs. Arrays of n doped SiNWs consistently showed frequency-dependent power dissipation. Nominally undoped SiNW arrays, however, showed no measurable microwave power dissipation up to 50 GHz.