  Compact layers containing embedded semiconductor particles consolidated using
pulsed electric current sintering exhibit intense, broadband near-infrared
reflectance. The composites consolidated from nano- or micro-silica powder have
a different porous microstructure which causes scattering at the air-matrix
interface and larger reflectance primarily in the visible region. The 3 mm
thick composite compacts reflect up to 72% of the incident radiation in the
near-infrared region with a semiconductor microinclusion volume fraction of 1%
which closely matches predictions from multiscale Monte Carlo modeling and
Kubelka-Munk theory. Further, the calculated spectra predict an improvement of
the reflectance by decreasing the average particle size or broadening the
standard deviation. The high reflectance is achieved with minimal dissipative
losses and facile manufacturing, and the composites described herein are
well-suited to control the radiative transfer of heat in devices at high
temperature and under harsh conditions.
