Luminescence and optical properties of siloxene

We review the optical and luminescence properties of siloxene (Si 6 O 3 H 6 ). The preparation and basic structural properties of siloxene are described, and theoretical results concerning optical transitions in different modifications of siloxene are discussed. The dominant structural building blocks in as-prepared siloxene are two-dimensional Si planes which gave rise to a direct band gap in the visible energy range. The optical properties of annealed siloxene originate from isolated Si 6 rings which act as radiative recombination centers. The luminescence of annealed siloxene and porous silicon are compared in detail. In particular, new experimental results based on optically detected magnetic resonance provide microscopic information about radiative states in porous Si which is incompatible with the conventional quantum confinement model.